| blob | 24ea6abae689f834b44f80c5fb4b4ba726c553e2 |
1 <!--
2 - Copyright (C) 2004-2009 Internet Systems Consortium, Inc. ("ISC")
3 - Copyright (C) 2000-2003 Internet Software Consortium.
4 -
5 - Permission to use, copy, modify, and/or distribute this software for any
6 - purpose with or without fee is hereby granted, provided that the above
7 - copyright notice and this permission notice appear in all copies.
8 -
9 - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 - PERFORMANCE OF THIS SOFTWARE.
16 -->
17 <!-- Id: Bv9ARM.ch06.html,v 1.249 2009/12/04 22:22:26 tbox Exp -->
18 <html>
19 <head>
27 </head>
31 <tr><th colspan="3" align="center">Chapter 6. <acronym class="acronym">BIND</acronym> 9 Configuration Reference</th></tr>
32 <tr>
37 </td>
38 </tr>
39 </table>
40 <hr>
41 </div>
44 <a name="Bv9ARM.ch06"></a>Chapter 6. <acronym class="acronym">BIND</acronym> 9 Configuration Reference</h2></div></div></div>
47 <dl>
48 <dt><span class="sect1"><a href="Bv9ARM.ch06.html#configuration_file_elements">Configuration File Elements</a></span></dt>
49 <dd><dl>
50 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#address_match_lists">Address Match Lists</a></span></dt>
52 </dl></dd>
53 <dt><span class="sect1"><a href="Bv9ARM.ch06.html#Configuration_File_Grammar">Configuration File Grammar</a></span></dt>
54 <dd><dl>
55 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2574515"><span><strong class="command">acl</strong></span> Statement Grammar</a></span></dt>
56 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#acl"><span><strong class="command">acl</strong></span> Statement Definition and
57 Usage</a></span></dt>
58 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2574773"><span><strong class="command">controls</strong></span> Statement Grammar</a></span></dt>
59 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#controls_statement_definition_and_usage"><span><strong class="command">controls</strong></span> Statement Definition and
60 Usage</a></span></dt>
61 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2575132"><span><strong class="command">include</strong></span> Statement Grammar</a></span></dt>
62 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2575149"><span><strong class="command">include</strong></span> Statement Definition and
63 Usage</a></span></dt>
64 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2575173"><span><strong class="command">key</strong></span> Statement Grammar</a></span></dt>
65 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2575196"><span><strong class="command">key</strong></span> Statement Definition and Usage</a></span></dt>
66 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2575287"><span><strong class="command">logging</strong></span> Statement Grammar</a></span></dt>
67 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2575413"><span><strong class="command">logging</strong></span> Statement Definition and
68 Usage</a></span></dt>
69 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2577480"><span><strong class="command">lwres</strong></span> Statement Grammar</a></span></dt>
70 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2577554"><span><strong class="command">lwres</strong></span> Statement Definition and Usage</a></span></dt>
71 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2577686"><span><strong class="command">masters</strong></span> Statement Grammar</a></span></dt>
72 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2577730"><span><strong class="command">masters</strong></span> Statement Definition and
73 Usage</a></span></dt>
74 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2577745"><span><strong class="command">options</strong></span> Statement Grammar</a></span></dt>
75 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#options"><span><strong class="command">options</strong></span> Statement Definition and
76 Usage</a></span></dt>
77 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#server_statement_grammar"><span><strong class="command">server</strong></span> Statement Grammar</a></span></dt>
78 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#server_statement_definition_and_usage"><span><strong class="command">server</strong></span> Statement Definition and
79 Usage</a></span></dt>
80 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#statschannels"><span><strong class="command">statistics-channels</strong></span> Statement Grammar</a></span></dt>
81 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2588103"><span><strong class="command">statistics-channels</strong></span> Statement Definition and
82 Usage</a></span></dt>
83 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2588326"><span><strong class="command">trusted-keys</strong></span> Statement Grammar</a></span></dt>
84 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2588377"><span><strong class="command">trusted-keys</strong></span> Statement Definition
85 and Usage</a></span></dt>
86 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2588424"><span><strong class="command">managed-keys</strong></span> Statement Grammar</a></span></dt>
87 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2588475"><span><strong class="command">managed-keys</strong></span> Statement Definition
88 and Usage</a></span></dt>
89 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#view_statement_grammar"><span><strong class="command">view</strong></span> Statement Grammar</a></span></dt>
90 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2588848"><span><strong class="command">view</strong></span> Statement Definition and Usage</a></span></dt>
91 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#zone_statement_grammar"><span><strong class="command">zone</strong></span>
92 Statement Grammar</a></span></dt>
93 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2590421"><span><strong class="command">zone</strong></span> Statement Definition and Usage</a></span></dt>
94 </dl></dd>
96 <dd><dl>
97 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#types_of_resource_records_and_when_to_use_them">Types of Resource Records and When to Use Them</a></span></dt>
98 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2595387">Discussion of MX Records</a></span></dt>
100 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2596003">Inverse Mapping in IPv4</a></span></dt>
101 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2596130">Other Zone File Directives</a></span></dt>
102 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#id2596403"><acronym class="acronym">BIND</acronym> Master File Extension: the <span><strong class="command">$GENERATE</strong></span> Directive</a></span></dt>
103 <dt><span class="sect2"><a href="Bv9ARM.ch06.html#zonefile_format">Additional File Formats</a></span></dt>
104 </dl></dd>
106 <dd><dl><dt><span class="sect2"><a href="Bv9ARM.ch06.html#statistics_counters">Statistics Counters</a></span></dt></dl></dd>
107 </dl>
108 </div>
109 <p>
112 areas
114 8 configuration files should work with few alterations in <acronym class="acronym">BIND</acronym>
115 9, although more complex configurations should be reviewed to check
116 if they can be more efficiently implemented using the new features
118 </p>
119 <p>
121 converted to the new format
122 using the shell script
124 </p>
128 <p>
129 Following is a list of elements used throughout the <acronym class="acronym">BIND</acronym> configuration
130 file documentation:
131 </p>
133 <colgroup>
134 <col>
135 <col>
136 </colgroup>
137 <tbody>
138 <tr>
139 <td>
140 <p>
142 </p>
143 </td>
144 <td>
145 <p>
148 </p>
149 </td>
150 </tr>
151 <tr>
152 <td>
153 <p>
155 </p>
156 </td>
157 <td>
158 <p>
159 A list of one or more
163 <a href="Bv9ARM.ch06.html#address_match_lists" title="Address Match Lists">the section called “Address Match Lists”</a>.
164 </p>
165 </td>
166 </tr>
167 <tr>
168 <td>
169 <p>
171 </p>
172 </td>
173 <td>
174 <p>
180 </p>
181 </td>
182 </tr>
183 <tr>
184 <td>
185 <p>
187 </p>
188 </td>
189 <td>
190 <p>
191 A quoted string which will be used as
193 </p>
194 </td>
195 </tr>
196 <tr>
197 <td>
198 <p>
200 </p>
201 </td>
202 <td>
203 <p>
205 elements.
206 </p>
207 </td>
208 </tr>
209 <tr>
210 <td>
211 <p>
213 </p>
214 </td>
215 <td>
216 <p>
217 One to four integers valued 0 through
219 <span><strong class="command">45.67</strong></span> or <span><strong class="command">89.123.45.67</strong></span>.
220 </p>
221 </td>
222 </tr>
223 <tr>
224 <td>
225 <p>
227 </p>
228 </td>
229 <td>
230 <p>
231 An IPv4 address with exactly four elements
233 </p>
234 </td>
235 </tr>
236 <tr>
237 <td>
238 <p>
240 </p>
241 </td>
242 <td>
243 <p>
245 IPv6 scoped addresses that have ambiguity on their
246 scope zones must be disambiguated by an appropriate
247 zone ID with the percent character (`%') as
248 delimiter. It is strongly recommended to use
249 string zone names rather than numeric identifiers,
250 in order to be robust against system configuration
251 changes. However, since there is no standard
252 mapping for such names and identifier values,
253 currently only interface names as link identifiers
254 are supported, assuming one-to-one mapping between
255 interfaces and links. For example, a link-local
259 Note that on most systems link-local addresses
260 always have the ambiguity, and need to be
261 disambiguated.
262 </p>
263 </td>
264 </tr>
265 <tr>
266 <td>
267 <p>
269 </p>
270 </td>
271 <td>
272 <p>
274 </p>
275 </td>
276 </tr>
277 <tr>
278 <td>
279 <p>
281 </p>
282 </td>
283 <td>
284 <p>
287 through 65535, with values
288 below 1024 typically restricted to use by processes running
289 as root.
290 In some cases, an asterisk (`*') character can be used as a
291 placeholder to
292 select a random high-numbered port.
293 </p>
294 </td>
295 </tr>
296 <tr>
297 <td>
298 <p>
300 </p>
301 </td>
302 <td>
303 <p>
305 followed by a slash (`/') and then the number of bits in the
306 netmask.
308 may omitted.
311 netmask <span><strong class="command">255.0.0.0</strong></span> and <span><strong class="command">1.2.3.0/28</strong></span> is
312 network <span><strong class="command">1.2.3.0</strong></span> with netmask <span><strong class="command">255.255.255.240</strong></span>.
313 </p>
314 <p>
315 When specifying a prefix involving a IPv6 scoped address
316 the scope may be omitted. In that case the prefix will
317 match packets from any scope.
318 </p>
319 </td>
320 </tr>
321 <tr>
322 <td>
323 <p>
325 </p>
326 </td>
327 <td>
328 <p>
330 the name of a shared key, to be used for transaction
331 security.
332 </p>
333 </td>
334 </tr>
335 <tr>
336 <td>
337 <p>
339 </p>
340 </td>
341 <td>
342 <p>
343 A list of one or more
345 separated by semicolons and ending with a semicolon.
346 </p>
347 </td>
348 </tr>
349 <tr>
350 <td>
351 <p>
353 </p>
354 </td>
355 <td>
356 <p>
357 A non-negative 32-bit integer
359 Its acceptable value might further
360 be limited by the context in which it is used.
361 </p>
362 </td>
363 </tr>
364 <tr>
365 <td>
366 <p>
368 </p>
369 </td>
370 <td>
371 <p>
372 A quoted string which will be used as
374 </p>
375 </td>
376 </tr>
377 <tr>
378 <td>
379 <p>
381 </p>
382 </td>
383 <td>
384 <p>
386 range.
387 A port range is specified in the form of
396 For example,
399 In either case an asterisk (`*') character is not
401 </p>
402 </td>
403 </tr>
404 <tr>
405 <td>
406 <p>
408 </p>
409 </td>
410 <td>
411 <p>
414 </p>
415 <p>
416 An <code class="varname">unlimited</code> <code class="varname">size_spec</code> requests unlimited
418 the limit that was in force when the server was started.
419 </p>
420 <p>
422 followed by a scaling factor:
423 <strong class="userinput"><code>K</code></strong> or <strong class="userinput"><code>k</code></strong>
424 for kilobytes,
425 <strong class="userinput"><code>M</code></strong> or <strong class="userinput"><code>m</code></strong>
426 for megabytes, and
427 <strong class="userinput"><code>G</code></strong> or <strong class="userinput"><code>g</code></strong> for gigabytes,
429 respectively.
430 </p>
431 <p>
432 The value must be representable as a 64-bit unsigned integer
435 way
436 to safely set a really large number.
437 </p>
438 </td>
439 </tr>
440 <tr>
441 <td>
442 <p>
444 </p>
445 </td>
446 <td>
447 <p>
448 Either <strong class="userinput"><code>yes</code></strong> or <strong class="userinput"><code>no</code></strong>.
449 The words <strong class="userinput"><code>true</code></strong> and <strong class="userinput"><code>false</code></strong> are
452 </p>
453 </td>
454 </tr>
455 <tr>
456 <td>
457 <p>
459 </p>
460 </td>
461 <td>
462 <p>
464 <strong class="userinput"><code>no</code></strong>, <strong class="userinput"><code>notify</code></strong>,
465 <strong class="userinput"><code>notify-passive</code></strong>, <strong class="userinput"><code>refresh</code></strong> or
468 <strong class="userinput"><code>refresh</code></strong>, and <strong class="userinput"><code>passive</code></strong>
469 are restricted to slave and stub zones.
470 </p>
471 </td>
472 </tr>
473 </tbody>
474 </table></div>
481 <pre class="programlisting"><code class="varname">address_match_list</code> = address_match_list_element ;
483 <code class="varname">address_match_list_element</code> = [<span class="optional"> ! </span>] (ip_address [<span class="optional">/length</span>] |
484 key key_id | acl_name | { address_match_list } )
485 </pre>
486 </div>
490 <p>
491 Address match lists are primarily used to determine access
492 control for various server operations. They are also used in
493 the <span><strong class="command">listen-on</strong></span> and <span><strong class="command">sortlist</strong></span>
494 statements. The elements which constitute an address match
495 list can be any of the following:
496 </p>
500 <li>
502 statement
503 </li>
504 <li>the name of an address match list defined with
506 </li>
508 </ul></div>
509 <p>
510 Elements can be negated with a leading exclamation mark (`!'),
512 "localnets" are predefined. More information on those names
513 can be found in the description of the acl statement.
514 </p>
515 <p>
516 The addition of the key clause made the name of this syntactic
517 element something of a misnomer, since security keys can be used
518 to validate access without regard to a host or network address.
519 Nonetheless, the term "address match list" is still used
520 throughout the documentation.
521 </p>
522 <p>
523 When a given IP address or prefix is compared to an address
524 match list, the comparison takes place in approximately O(1)
525 time. However, key comparisons require that the list of keys
526 be traversed until a matching key is found, and therefore may
527 be somewhat slower.
528 </p>
529 <p>
530 The interpretation of a match depends on whether the list is being
531 used for access control, defining <span><strong class="command">listen-on</strong></span> ports, or in a
533 </p>
534 <p>
535 When used as an access control list, a non-negated match
536 allows access and a negated match denies access. If
537 there is no match, access is denied. The clauses
549 lists. Similarly, the <span><strong class="command">listen-on</strong></span> option will cause the
550 server to refuse queries on any of the machine's
551 addresses which do not match the list.
552 </p>
553 <p>
554 Order of insertion is significant. If more than one element
555 in an ACL is found to match a given IP address or prefix,
556 preference will be given to the one that came
558 Because of this first-match behavior, an element that
559 defines a subset of another element in the list should
560 come before the broader element, regardless of whether
561 either is negated. For example, in
563 the 1.2.3.13 element is completely useless because the
566 that problem by having 1.2.3.13 blocked by the negation, but
567 all other 1.2.3.* hosts fall through.
568 </p>
569 </div>
570 </div>
574 <p>
576 comments to appear
578 file. To appeal to programmers of all kinds, they can be written
579 in the C, C++, or shell/perl style.
580 </p>
584 <p>
585 </p>
586 <pre class="programlisting">/* This is a <acronym class="acronym">BIND</acronym> comment as in C */</pre>
587 <p>
588 </p>
589 <pre class="programlisting">// This is a <acronym class="acronym">BIND</acronym> comment as in C++</pre>
590 <p>
591 </p>
592 <pre class="programlisting"># This is a <acronym class="acronym">BIND</acronym> comment as in common UNIX shells
593 # and perl</pre>
594 <p>
595 </p>
596 </div>
600 <p>
601 Comments may appear anywhere that whitespace may appear in
603 </p>
604 <p>
605 C-style comments start with the two characters /* (slash,
606 star) and end with */ (star, slash). Because they are completely
607 delimited with these characters, they can be used to comment only
608 a portion of a line or to span multiple lines.
609 </p>
610 <p>
611 C-style comments cannot be nested. For example, the following
612 is not valid because the entire comment ends with the first */:
613 </p>
614 <p>
616 </p>
618 This is still part of the comment.
619 /* This is an incorrect attempt at nesting a comment. */
620 This is no longer in any comment. */
621 </pre>
622 <p>
624 </p>
625 <p>
626 C++-style comments start with the two characters // (slash,
627 slash) and continue to the end of the physical line. They cannot
628 be continued across multiple physical lines; to have one logical
629 comment span multiple lines, each line must use the // pair.
630 For example:
631 </p>
632 <p>
634 </p>
636 // is a new comment, even though it is logically
637 // part of the previous comment.
638 </pre>
639 <p>
641 </p>
642 <p>
643 Shell-style (or perl-style, if you prefer) comments start
645 and continue to the end of the
646 physical line, as in C++ comments.
647 For example:
648 </p>
649 <p>
651 </p>
653 # is a new comment, even though it is logically
654 # part of the previous comment.
655 </pre>
656 <p>
658 </p>
661 <p>
662 You cannot use the semicolon (`;') character
663 to start a comment such as you would in a zone file. The
664 semicolon indicates the end of a configuration
665 statement.
666 </p>
667 </div>
668 </div>
669 </div>
670 </div>
674 <p>
676 statements and comments.
677 Statements end with a semicolon. Statements and comments are the
678 only elements that can appear without enclosing braces. Many
679 statements contain a block of sub-statements, which are also
680 terminated with a semicolon.
681 </p>
682 <p>
683 The following statements are supported:
684 </p>
686 <colgroup>
687 <col>
688 <col>
689 </colgroup>
690 <tbody>
691 <tr>
692 <td>
694 </td>
695 <td>
696 <p>
697 defines a named IP address
698 matching list, for access control and other uses.
699 </p>
700 </td>
701 </tr>
702 <tr>
703 <td>
705 </td>
706 <td>
707 <p>
708 declares control channels to be used
710 </p>
711 </td>
712 </tr>
713 <tr>
714 <td>
716 </td>
717 <td>
718 <p>
719 includes a file.
720 </p>
721 </td>
722 </tr>
723 <tr>
724 <td>
726 </td>
727 <td>
728 <p>
729 specifies key information for use in
730 authentication and authorization using TSIG.
731 </p>
732 </td>
733 </tr>
734 <tr>
735 <td>
737 </td>
738 <td>
739 <p>
740 specifies what the server logs, and where
741 the log messages are sent.
742 </p>
743 </td>
744 </tr>
745 <tr>
746 <td>
748 </td>
749 <td>
750 <p>
752 also act as a light-weight resolver daemon (<span><strong class="command">lwresd</strong></span>).
753 </p>
754 </td>
755 </tr>
756 <tr>
757 <td>
759 </td>
760 <td>
761 <p>
762 defines a named masters list for
763 inclusion in stub and slave zone masters clauses.
764 </p>
765 </td>
766 </tr>
767 <tr>
768 <td>
770 </td>
771 <td>
772 <p>
773 controls global server configuration
774 options and sets defaults for other statements.
775 </p>
776 </td>
777 </tr>
778 <tr>
779 <td>
781 </td>
782 <td>
783 <p>
784 sets certain configuration options on
785 a per-server basis.
786 </p>
787 </td>
788 </tr>
789 <tr>
790 <td>
792 </td>
793 <td>
794 <p>
795 declares communication channels to get access to
797 </p>
798 </td>
799 </tr>
800 <tr>
801 <td>
803 </td>
804 <td>
805 <p>
806 defines trusted DNSSEC keys.
807 </p>
808 </td>
809 </tr>
810 <tr>
811 <td>
813 </td>
814 <td>
815 <p>
816 lists DNSSEC keys to be kept up to date
817 using RFC 5011 trust anchor maintenance.
818 </p>
819 </td>
820 </tr>
821 <tr>
822 <td>
824 </td>
825 <td>
826 <p>
827 defines a view.
828 </p>
829 </td>
830 </tr>
831 <tr>
832 <td>
834 </td>
835 <td>
836 <p>
837 defines a zone.
838 </p>
839 </td>
840 </tr>
841 </tbody>
842 </table></div>
843 <p>
846 per
847 configuration.
848 </p>
851 <a name="id2574515"></a><span><strong class="command">acl</strong></span> Statement Grammar</h3></div></div></div>
853 address_match_list
854 };
855 </pre>
856 </div>
860 Usage</h3></div></div></div>
861 <p>
863 name to an address match list. It gets its name from a primary
864 use of address match lists: Access Control Lists (ACLs).
865 </p>
866 <p>
867 Note that an address match list's name must be defined
869 elsewhere; no forward references are allowed.
870 </p>
871 <p>
872 The following ACLs are built-in:
873 </p>
875 <colgroup>
876 <col>
877 <col>
878 </colgroup>
879 <tbody>
880 <tr>
881 <td>
883 </td>
884 <td>
885 <p>
886 Matches all hosts.
887 </p>
888 </td>
889 </tr>
890 <tr>
891 <td>
893 </td>
894 <td>
895 <p>
896 Matches no hosts.
897 </p>
898 </td>
899 </tr>
900 <tr>
901 <td>
903 </td>
904 <td>
905 <p>
906 Matches the IPv4 and IPv6 addresses of all network
907 interfaces on the system.
908 </p>
909 </td>
910 </tr>
911 <tr>
912 <td>
914 </td>
915 <td>
916 <p>
917 Matches any host on an IPv4 or IPv6 network
918 for which the system has an interface.
919 Some systems do not provide a way to determine the prefix
920 lengths of
921 local IPv6 addresses.
923 only matches the local
925 </p>
926 </td>
927 </tr>
928 </tbody>
929 </table></div>
930 </div>
933 <a name="id2574773"></a><span><strong class="command">controls</strong></span> Statement Grammar</h3></div></div></div>
935 [ inet ( ip_addr | * ) [ port ip_port ]
938 [ inet ...; ]
939 [ unix <em class="replaceable"><code>path</code></em> perm <em class="replaceable"><code>number</code></em> owner <em class="replaceable"><code>number</code></em> group <em class="replaceable"><code>number</code></em>
941 [ unix ...; ]
942 };
943 </pre>
944 </div>
947 <a name="controls_statement_definition_and_usage"></a><span><strong class="command">controls</strong></span> Statement Definition and
948 Usage</h3></div></div></div>
949 <p>
951 channels to be used by system administrators to control the
952 operation of the name server. These control channels are
954 commands to and retrieve non-DNS results from a name server.
955 </p>
956 <p>
960 address. An <span><strong class="command">ip_addr</strong></span> of <code class="literal">*</code> (asterisk) is
961 interpreted as the IPv4 wildcard address; connections will be
962 accepted on any of the system's IPv4 addresses.
963 To listen on the IPv6 wildcard address,
964 use an <span><strong class="command">ip_addr</strong></span> of <code class="literal">::</code>.
968 </p>
969 <p>
970 If no port is specified, port 953 is used. The asterisk
971 "<code class="literal">*</code>" cannot be used for <span><strong class="command">ip_port</strong></span>.
972 </p>
973 <p>
974 The ability to issue commands over the control channel is
977 Connections to the control channel are permitted based on the
981 are ignored.
982 </p>
983 <p>
985 socket listening at the specified path in the file system.
987 <span><strong class="command">owner</strong></span> and <span><strong class="command">group</strong></span> clauses.
988 Note on some platforms (SunOS and Solaris) the permissions
990 as the permissions on the socket itself are ignored.
991 </p>
992 <p>
993 The primary authorization mechanism of the command
996 Each <span><strong class="command">key_id</strong></span> in the <span><strong class="command">key_list</strong></span>
997 is authorized to execute commands over the control channel.
998 See <a href="Bv9ARM.ch03.html#rndc">Remote Name Daemon Control application</a> in <a href="Bv9ARM.ch03.html#admin_tools" title="Administrative Tools">the section called “Administrative Tools”</a>)
1000 </p>
1001 <p>
1004 control channel listening on the loopback address 127.0.0.1
1005 and its IPv6 counterpart ::1.
1006 In this case, and also when the <span><strong class="command">controls</strong></span> statement
1008 <span><strong class="command">named</strong></span> will attempt to load the command channel key
1014 </p>
1015 <p>
1018 which did not have digital signatures on its command channel
1026 installed.
1027 </p>
1028 <p>
1030 is only intended to allow the backward-compatible usage of
1032 feature does not
1033 have a high degree of configurability. You cannot easily change
1034 the key name or the size of the secret, so you should make a
1036 wish to change
1038 also has its
1039 permissions set such that only the owner of the file (the user that
1041 If you
1042 desire greater flexibility in allowing other users to access
1044 a
1046 readable by a group
1047 that contains the users who should have access.
1048 </p>
1049 <p>
1050 To disable the command channel, use an empty
1053 </p>
1054 </div>
1057 <a name="id2575132"></a><span><strong class="command">include</strong></span> Statement Grammar</h3></div></div></div>
1058 <pre class="programlisting"><span><strong class="command">include</strong></span> <em class="replaceable"><code>filename</code></em>;</pre>
1059 </div>
1062 <a name="id2575149"></a><span><strong class="command">include</strong></span> Statement Definition and
1063 Usage</h3></div></div></div>
1064 <p>
1068 statement facilitates the administration of configuration
1069 files
1070 by permitting the reading or writing of some things but not
1071 others. For example, the statement could include private keys
1072 that are readable only by the name server.
1073 </p>
1074 </div>
1077 <a name="id2575173"></a><span><strong class="command">key</strong></span> Statement Grammar</h3></div></div></div>
1078 <pre class="programlisting"><span><strong class="command">key</strong></span> <em class="replaceable"><code>key_id</code></em> {
1081 };
1082 </pre>
1083 </div>
1086 <a name="id2575196"></a><span><strong class="command">key</strong></span> Statement Definition and Usage</h3></div></div></div>
1087 <p>
1089 secret key for use with TSIG (see <a href="Bv9ARM.ch04.html#tsig" title="TSIG">the section called “TSIG”</a>)
1090 or the command channel
1091 (see <a href="Bv9ARM.ch06.html#controls_statement_definition_and_usage" title="controls Statement Definition and
1092 Usage">the section called “<span><strong class="command">controls</strong></span> Statement Definition and
1094 </p>
1095 <p>
1097 top level
1100 statements can be used in all views. Keys intended for use in
1102 (see <a href="Bv9ARM.ch06.html#controls_statement_definition_and_usage" title="controls Statement Definition and
1103 Usage">the section called “<span><strong class="command">controls</strong></span> Statement Definition and
1105 must be defined at the top level.
1106 </p>
1107 <p>
1109 key name, is a domain name uniquely identifying the key. It can
1111 statement to cause requests sent to that
1112 server to be signed with this key, or in address match lists to
1113 verify that incoming requests have been signed with a key
1114 matching this name, algorithm, and secret.
1115 </p>
1116 <p>
1118 that specifies a security/authentication algorithm. Named
1123 Truncated hashes are supported by appending the minimum
1124 number of required bits preceded by a dash, e.g.
1127 to be used by the algorithm, and is treated as a base-64
1128 encoded string.
1129 </p>
1130 </div>
1133 <a name="id2575287"></a><span><strong class="command">logging</strong></span> Statement Grammar</h3></div></div></div>
1135 [ <span><strong class="command">channel</strong></span> <em class="replaceable"><code>channel_name</code></em> {
1136 ( <span><strong class="command">file</strong></span> <em class="replaceable"><code>path_name</code></em>
1137 [ <span><strong class="command">versions</strong></span> ( <em class="replaceable"><code>number</code></em> | <span><strong class="command">unlimited</strong></span> ) ]
1138 [ <span><strong class="command">size</strong></span> <em class="replaceable"><code>size spec</code></em> ]
1139 | <span><strong class="command">syslog</strong></span> <em class="replaceable"><code>syslog_facility</code></em>
1142 [ <span><strong class="command">severity</strong></span> (<code class="option">critical</code> | <code class="option">error</code> | <code class="option">warning</code> | <code class="option">notice</code> |
1143 <code class="option">info</code> | <code class="option">debug</code> [ <em class="replaceable"><code>level</code></em> ] | <code class="option">dynamic</code> ); ]
1144 [ <span><strong class="command">print-category</strong></span> <code class="option">yes</code> or <code class="option">no</code>; ]
1145 [ <span><strong class="command">print-severity</strong></span> <code class="option">yes</code> or <code class="option">no</code>; ]
1146 [ <span><strong class="command">print-time</strong></span> <code class="option">yes</code> or <code class="option">no</code>; ]
1147 }; ]
1148 [ <span><strong class="command">category</strong></span> <em class="replaceable"><code>category_name</code></em> {
1149 <em class="replaceable"><code>channel_name</code></em> ; [ <em class="replaceable"><code>channel_name</code></em> ; ... ]
1150 }; ]
1151 ...
1152 };
1153 </pre>
1154 </div>
1157 <a name="id2575413"></a><span><strong class="command">logging</strong></span> Statement Definition and
1158 Usage</h3></div></div></div>
1159 <p>
1161 wide
1162 variety of logging options for the name server. Its <span><strong class="command">channel</strong></span> phrase
1163 associates output methods, format options and severity levels with
1164 a name that can then be used with the <span><strong class="command">category</strong></span> phrase
1165 to select how various classes of messages are logged.
1166 </p>
1167 <p>
1169 define
1170 as many channels and categories as are wanted. If there is no <span><strong class="command">logging</strong></span> statement,
1171 the logging configuration will be:
1172 </p>
1174 category default { default_syslog; default_debug; };
1175 category unmatched { null; };
1176 };
1177 </pre>
1178 <p>
1180 is only established when
1181 the entire configuration file has been parsed. In <acronym class="acronym">BIND</acronym> 8, it was
1183 statement
1184 was parsed. When the server is starting up, all logging messages
1185 regarding syntax errors in the configuration file go to the default
1187 was specified.
1188 </p>
1191 <a name="id2575465"></a>The <span><strong class="command">channel</strong></span> Phrase</h4></div></div></div>
1192 <p>
1194 you can make as many of them as you want.
1195 </p>
1196 <p>
1197 Every channel definition must include a destination clause that
1198 says whether messages selected for the channel go to a file, to a
1199 particular syslog facility, to the standard error stream, or are
1200 discarded. It can optionally also limit the message severity level
1201 that will be accepted by the channel (the default is
1204 category name
1205 and/or severity level (the default is not to include any).
1206 </p>
1207 <p>
1209 causes all messages sent to the channel to be discarded;
1210 in that case, other options for the channel are meaningless.
1211 </p>
1212 <p>
1214 the channel
1215 to a disk file. It can include limitations
1216 both on how large the file is allowed to become, and how many
1217 versions
1218 of the file will be saved each time the file is opened.
1219 </p>
1220 <p>
1222 option, then
1224 versions of the file by
1225 renaming them when opening. For example, if you choose to keep
1226 three old versions
1228 before it is opened
1230 <code class="filename">lamers.log.2</code>, <code class="filename">lamers.log.0</code> is renamed
1234 not limit
1235 the number of versions.
1237 the log file,
1238 then renaming is only done when the file being opened exceeds the
1239 indicated size. No backup versions are kept by default; any
1240 existing
1241 log file is simply appended.
1242 </p>
1243 <p>
1245 to limit log
1246 growth. If the file ever exceeds the size, then <span><strong class="command">named</strong></span> will
1247 stop writing to the file unless it has a <span><strong class="command">versions</strong></span> option
1248 associated with it. If backup versions are kept, the files are
1249 rolled as
1250 described above and a new one begun. If there is no
1252 be written to the log
1253 until some out-of-band mechanism removes or truncates the log to
1254 less than the
1255 maximum size. The default behavior is not to limit the size of
1256 the
1257 file.
1258 </p>
1259 <p>
1262 </p>
1265 print-time yes;
1266 print-category yes;
1267 };
1268 </pre>
1269 <p>
1271 directs the
1272 channel to the system log. Its argument is a
1274 page. Known facilities are <span><strong class="command">kern</strong></span>, <span><strong class="command">user</strong></span>,
1275 <span><strong class="command">mail</strong></span>, <span><strong class="command">daemon</strong></span>, <span><strong class="command">auth</strong></span>,
1276 <span><strong class="command">syslog</strong></span>, <span><strong class="command">lpr</strong></span>, <span><strong class="command">news</strong></span>,
1277 <span><strong class="command">uucp</strong></span>, <span><strong class="command">cron</strong></span>, <span><strong class="command">authpriv</strong></span>,
1278 <span><strong class="command">ftp</strong></span>, <span><strong class="command">local0</strong></span>, <span><strong class="command">local1</strong></span>,
1279 <span><strong class="command">local2</strong></span>, <span><strong class="command">local3</strong></span>, <span><strong class="command">local4</strong></span>,
1280 <span><strong class="command">local5</strong></span>, <span><strong class="command">local6</strong></span> and
1282 are supported on
1283 all operating systems.
1285 sent to
1286 this facility is described in the <span><strong class="command">syslog.conf</strong></span> man
1287 page. If you have a system which uses a very old version of <span><strong class="command">syslog</strong></span> that
1288 only uses two arguments to the <span><strong class="command">openlog()</strong></span> function,
1289 then this clause is silently ignored.
1290 </p>
1291 <p>
1292 The <span><strong class="command">severity</strong></span> clause works like <span><strong class="command">syslog</strong></span>'s
1293 "priorities", except that they can also be used if you are writing
1295 Messages which are not at least of the severity level given will
1296 not be selected for the channel; messages of higher severity
1297 levels
1298 will be accepted.
1299 </p>
1300 <p>
1301 If you are using <span><strong class="command">syslog</strong></span>, then the <span><strong class="command">syslog.conf</strong></span> priorities
1302 will also determine what eventually passes through. For example,
1303 defining a channel facility and severity as <span><strong class="command">daemon</strong></span> and <span><strong class="command">debug</strong></span> but
1304 only logging <span><strong class="command">daemon.warning</strong></span> via <span><strong class="command">syslog.conf</strong></span> will
1307 be dropped. If the situation were reversed, with <span><strong class="command">named</strong></span> writing
1310 print all messages it received from the channel.
1311 </p>
1312 <p>
1314 directs the
1315 channel to the server's standard error stream. This is intended
1316 for
1317 use when the server is running as a foreground process, for
1318 example
1319 when debugging a configuration.
1320 </p>
1321 <p>
1322 The server can supply extensive debugging information when
1323 it is in debugging mode. If the server's global debug level is
1324 greater
1325 than zero, then debugging mode will be active. The global debug
1329 The global debug level
1330 can be set to zero, and debugging mode turned off, by running <span><strong class="command">rndc
1331 notrace</strong></span>. All debugging messages in the server have a debug
1332 level, and higher debug levels give more detailed output. Channels
1333 that specify a specific debug severity, for example:
1334 </p>
1336 file "foo";
1337 severity debug 3;
1338 };
1339 </pre>
1340 <p>
1341 will get debugging output of level 3 or less any time the
1342 server is in debugging mode, regardless of the global debugging
1344 severity use the
1345 server's global debug level to determine what messages to print.
1346 </p>
1347 <p>
1349 then
1352 but is usually
1354 the date and
1356 requested, then the
1357 category of the message will be logged as well. Finally, if <span><strong class="command">print-severity</strong></span> is
1358 on, then the severity level of the message will be logged. The <span><strong class="command">print-</strong></span> options may
1359 be used in any combination, and will always be printed in the
1360 following
1361 order: time, category, severity. Here is an example where all
1363 are on:
1364 </p>
1365 <p>
1367 </p>
1368 <p>
1369 There are four predefined channels that are used for
1371 How they are
1372 used is described in <a href="Bv9ARM.ch06.html#the_category_phrase" title="The category Phrase">the section called “The <span><strong class="command">category</strong></span> Phrase”</a>.
1373 </p>
1375 // send to syslog's daemon facility
1376 syslog daemon;
1377 // only send priority info and higher
1378 severity info;
1380 channel default_debug {
1381 // write to named.run in the working directory
1382 // Note: stderr is used instead of "named.run" if
1383 // the server is started with the '-f' option.
1384 file "named.run";
1385 // log at the server's current debug level
1386 severity dynamic;
1387 };
1389 channel default_stderr {
1390 // writes to stderr
1391 stderr;
1392 // only send priority info and higher
1393 severity info;
1394 };
1396 channel null {
1397 // toss anything sent to this channel
1398 null;
1399 };
1400 </pre>
1401 <p>
1403 special
1404 property that it only produces output when the server's debug
1405 level is
1407 in the server's working directory.
1408 </p>
1409 <p>
1413 changed to the
1414 new UID, and any debug output generated while <span><strong class="command">named</strong></span> is
1415 starting up and still running as root is discarded. If you need
1417 option and redirect standard error to a file.
1418 </p>
1419 <p>
1420 Once a channel is defined, it cannot be redefined. Thus you
1421 cannot alter the built-in channels directly, but you can modify
1422 the default logging by pointing categories at channels you have
1423 defined.
1424 </p>
1425 </div>
1428 <a name="the_category_phrase"></a>The <span><strong class="command">category</strong></span> Phrase</h4></div></div></div>
1429 <p>
1430 There are many categories, so you can send the logs you want
1431 to see wherever you want, without seeing logs you don't want. If
1432 you don't specify a list of channels for a category, then log
1433 messages
1434 in that category will be sent to the <span><strong class="command">default</strong></span> category
1435 instead. If you don't specify a default category, the following
1436 "default default" is used:
1437 </p>
1439 </pre>
1440 <p>
1441 As an example, let's say you want to log security events to
1442 a file, but you also want keep the default logging behavior. You'd
1443 specify the following:
1444 </p>
1446 file "my_security_file";
1447 severity info;
1448 };
1449 category security {
1450 my_security_channel;
1451 default_syslog;
1452 default_debug;
1453 };</pre>
1454 <p>
1455 To discard all messages in a category, specify the <span><strong class="command">null</strong></span> channel:
1456 </p>
1458 category notify { null; };
1459 </pre>
1460 <p>
1461 Following are the available categories and brief descriptions
1462 of the types of log information they contain. More
1464 </p>
1466 <colgroup>
1467 <col>
1468 <col>
1469 </colgroup>
1470 <tbody>
1471 <tr>
1472 <td>
1474 </td>
1475 <td>
1476 <p>
1477 The default category defines the logging
1478 options for those categories where no specific
1479 configuration has been
1480 defined.
1481 </p>
1482 </td>
1483 </tr>
1484 <tr>
1485 <td>
1487 </td>
1488 <td>
1489 <p>
1490 The catch-all. Many things still aren't
1491 classified into categories, and they all end up here.
1492 </p>
1493 </td>
1494 </tr>
1495 <tr>
1496 <td>
1498 </td>
1499 <td>
1500 <p>
1501 Messages relating to the databases used
1502 internally by the name server to store zone and cache
1503 data.
1504 </p>
1505 </td>
1506 </tr>
1507 <tr>
1508 <td>
1510 </td>
1511 <td>
1512 <p>
1513 Approval and denial of requests.
1514 </p>
1515 </td>
1516 </tr>
1517 <tr>
1518 <td>
1520 </td>
1521 <td>
1522 <p>
1523 Configuration file parsing and processing.
1524 </p>
1525 </td>
1526 </tr>
1527 <tr>
1528 <td>
1530 </td>
1531 <td>
1532 <p>
1533 DNS resolution, such as the recursive
1534 lookups performed on behalf of clients by a caching name
1535 server.
1536 </p>
1537 </td>
1538 </tr>
1539 <tr>
1540 <td>
1542 </td>
1543 <td>
1544 <p>
1545 Zone transfers the server is receiving.
1546 </p>
1547 </td>
1548 </tr>
1549 <tr>
1550 <td>
1552 </td>
1553 <td>
1554 <p>
1555 Zone transfers the server is sending.
1556 </p>
1557 </td>
1558 </tr>
1559 <tr>
1560 <td>
1562 </td>
1563 <td>
1564 <p>
1565 The NOTIFY protocol.
1566 </p>
1567 </td>
1568 </tr>
1569 <tr>
1570 <td>
1572 </td>
1573 <td>
1574 <p>
1575 Processing of client requests.
1576 </p>
1577 </td>
1578 </tr>
1579 <tr>
1580 <td>
1582 </td>
1583 <td>
1584 <p>
1586 class of or for which there was no matching <span><strong class="command">view</strong></span>.
1587 A one line summary is also logged to the <span><strong class="command">client</strong></span> category.
1588 This category is best sent to a file or stderr, by
1589 default it is sent to
1591 </p>
1592 </td>
1593 </tr>
1594 <tr>
1595 <td>
1597 </td>
1598 <td>
1599 <p>
1600 Network operations.
1601 </p>
1602 </td>
1603 </tr>
1604 <tr>
1605 <td>
1607 </td>
1608 <td>
1609 <p>
1610 Dynamic updates.
1611 </p>
1612 </td>
1613 </tr>
1614 <tr>
1615 <td>
1617 </td>
1618 <td>
1619 <p>
1620 Approval and denial of update requests.
1621 </p>
1622 </td>
1623 </tr>
1624 <tr>
1625 <td>
1627 </td>
1628 <td>
1629 <p>
1630 Specify where queries should be logged to.
1631 </p>
1632 <p>
1633 At startup, specifying the category <span><strong class="command">queries</strong></span> will also
1634 enable query logging unless <span><strong class="command">querylog</strong></span> option has been
1635 specified.
1636 </p>
1638 <p>
1639 The query log entry reports the client's IP
1640 address and port number, and the query name,
1641 class and type. Next it reports whether the
1642 Recursion Desired flag was set (+ if set, -
1643 if not set), if the query was signed (S),
1644 EDNS was in use (E), if TCP was used (T), if
1645 DO (DNSSEC Ok) was set (D), or if CD (Checking
1646 Disabled) was set (C). After this the
1647 destination address the query was sent to is
1648 reported.
1649 </p>
1651 <p>
1653 </p>
1654 <p>
1656 </p>
1657 </td>
1658 </tr>
1659 <tr>
1660 <td>
1662 </td>
1663 <td>
1664 <p>
1665 Information about queries that resulted in some
1666 failure.
1667 </p>
1668 </td>
1669 </tr>
1670 <tr>
1671 <td>
1673 </td>
1674 <td>
1675 <p>
1676 Dispatching of incoming packets to the
1677 server modules where they are to be processed.
1678 </p>
1679 </td>
1680 </tr>
1681 <tr>
1682 <td>
1684 </td>
1685 <td>
1686 <p>
1687 DNSSEC and TSIG protocol processing.
1688 </p>
1689 </td>
1690 </tr>
1691 <tr>
1692 <td>
1694 </td>
1695 <td>
1696 <p>
1697 Lame servers. These are misconfigurations
1698 in remote servers, discovered by BIND 9 when trying to
1699 query those servers during resolution.
1700 </p>
1701 </td>
1702 </tr>
1703 <tr>
1704 <td>
1706 </td>
1707 <td>
1708 <p>
1709 Delegation only. Logs queries that have been
1710 forced to NXDOMAIN as the result of a
1711 delegation-only zone or a
1713 or stub zone declaration.
1714 </p>
1715 </td>
1716 </tr>
1717 <tr>
1718 <td>
1720 </td>
1721 <td>
1722 <p>
1723 Log queries that have been forced to use plain
1724 DNS due to timeouts. This is often due to
1725 the remote servers not being RFC 1034 compliant
1726 (not always returning FORMERR or similar to
1727 EDNS queries and other extensions to the DNS
1728 when they are not understood). In other words, this is
1729 targeted at servers that fail to respond to
1730 DNS queries that they don't understand.
1731 </p>
1732 <p>
1733 Note: the log message can also be due to
1734 packet loss. Before reporting servers for
1735 non-RFC 1034 compliance they should be re-tested
1736 to determine the nature of the non-compliance.
1737 This testing should prevent or reduce the
1738 number of false-positive reports.
1739 </p>
1740 <p>
1742 treating such timeouts as due to RFC 1034 non
1743 compliance and start treating it as plain
1744 packet loss. Falsely classifying packet
1745 loss as due to RFC 1034 non compliance impacts
1746 on DNSSEC validation which requires EDNS for
1747 the DNSSEC records to be returned.
1748 </p>
1749 </td>
1750 </tr>
1751 </tbody>
1752 </table></div>
1753 </div>
1756 <a name="id2576961"></a>The <span><strong class="command">query-errors</strong></span> Category</h4></div></div></div>
1757 <p>
1759 specifically intended for debugging purposes: To identify
1760 why and how specific queries result in responses which
1761 indicate an error.
1762 Messages of this category are therefore only logged
1764 </p>
1765 <p>
1766 At the debug levels of 1 or higher, each response with the
1767 rcode of SERVFAIL is logged as follows:
1768 </p>
1769 <p>
1770 <code class="computeroutput">client 127.0.0.1#61502: query failed (SERVFAIL) for www.example.com/IN/AAAA at query.c:3880</code>
1771 </p>
1772 <p>
1773 This means an error resulting in SERVFAIL was
1774 detected at line 3880 of source file
1776 Log messages of this level will particularly
1777 help identify the cause of SERVFAIL for an
1778 authoritative server.
1779 </p>
1780 <p>
1781 At the debug levels of 2 or higher, detailed context
1782 information of recursive resolutions that resulted in
1783 SERVFAIL is logged.
1784 The log message will look like as follows:
1785 </p>
1786 <p>
1788 </p>
1790 fetch completed at resolver.c:2970 for www.example.com/A
1791 in 30.000183: timed out/success [domain:example.com,
1794 </pre>
1795 <p>
1796 </p>
1797 <p>
1798 The first part before the colon shows that a recursive
1799 resolution for AAAA records of www.example.com completed
1800 in 30.000183 seconds and the final result that led to the
1801 SERVFAIL was determined at line 2970 of source file
1803 </p>
1804 <p>
1805 The following part shows the detected final result and the
1806 latest result of DNSSEC validation.
1807 The latter is always success when no validation attempt
1808 is made.
1809 In this example, this query resulted in SERVFAIL probably
1810 because all name servers are down or unreachable, leading
1811 to a timeout in 30 seconds.
1812 DNSSEC validation was probably not attempted.
1813 </p>
1814 <p>
1815 The last part enclosed in square brackets shows statistics
1816 information collected for this particular resolution
1817 attempt.
1819 that the resolver reached;
1820 it is the zone where the error was finally detected.
1821 The meaning of the other fields is summarized in the
1822 following table.
1823 </p>
1825 <colgroup>
1826 <col>
1827 <col>
1828 </colgroup>
1829 <tbody>
1830 <tr>
1831 <td>
1833 </td>
1834 <td>
1835 <p>
1836 The number of referrals the resolver received
1837 throughout the resolution process.
1838 In the above example this is 2, which are most
1839 likely com and example.com.
1840 </p>
1841 </td>
1842 </tr>
1843 <tr>
1844 <td>
1846 </td>
1847 <td>
1848 <p>
1849 The number of cycles that the resolver tried
1851 zone.
1852 In each cycle the resolver sends one query
1853 (possibly resending it, depending on the response)
1854 to each known name server of
1856 </p>
1857 </td>
1858 </tr>
1859 <tr>
1860 <td>
1862 </td>
1863 <td>
1864 <p>
1865 The number of queries the resolver sent at the
1867 </p>
1868 </td>
1869 </tr>
1870 <tr>
1871 <td>
1873 </td>
1874 <td>
1875 <p>
1876 The number of timeouts since the resolver
1877 received the last response.
1878 </p>
1879 </td>
1880 </tr>
1881 <tr>
1882 <td>
1884 </td>
1885 <td>
1886 <p>
1887 The number of lame servers the resolver detected
1889 A server is detected to be lame either by an
1890 invalid response or as a result of lookup in
1891 BIND9's address database (ADB), where lame
1892 servers are cached.
1893 </p>
1894 </td>
1895 </tr>
1896 <tr>
1897 <td>
1899 </td>
1900 <td>
1901 <p>
1902 The number of erroneous results that the
1903 resolver encountered in sending queries
1905 One common case is the remote server is
1906 unreachable and the resolver receives an ICMP
1907 unreachable error message.
1908 </p>
1909 </td>
1910 </tr>
1911 <tr>
1912 <td>
1914 </td>
1915 <td>
1916 <p>
1917 The number of unexpected responses (other than
1920 </p>
1921 </td>
1922 </tr>
1923 <tr>
1924 <td>
1926 </td>
1927 <td>
1928 <p>
1929 Failures in finding remote server addresses
1931 One common case of this is that the remote
1932 server's name does not have any address records.
1933 </p>
1934 </td>
1935 </tr>
1936 <tr>
1937 <td>
1939 </td>
1940 <td>
1941 <p>
1942 Failures of resolving remote server addresses.
1943 This is a total number of failures throughout
1944 the resolution process.
1945 </p>
1946 </td>
1947 </tr>
1948 <tr>
1949 <td>
1951 </td>
1952 <td>
1953 <p>
1954 Failures of DNSSEC validation.
1955 Validation failures are counted throughout
1956 the resolution process (not limited to
1959 </p>
1960 </td>
1961 </tr>
1962 </tbody>
1963 </table></div>
1964 <p>
1965 At the debug levels of 3 or higher, the same messages
1966 as those at the debug 1 level are logged for other errors
1967 than SERVFAIL.
1968 Note that negative responses such as NXDOMAIN are not
1969 regarded as errors here.
1970 </p>
1971 <p>
1972 At the debug levels of 4 or higher, the same messages
1973 as those at the debug 2 level are logged for other errors
1974 than SERVFAIL.
1975 Unlike the above case of level 3, messages are logged for
1976 negative responses.
1977 This is because any unexpected results can be difficult to
1978 debug in the recursion case.
1979 </p>
1980 </div>
1981 </div>
1984 <a name="id2577480"></a><span><strong class="command">lwres</strong></span> Statement Grammar</h3></div></div></div>
1985 <p>
1988 </p>
1990 [<span class="optional"> listen-on { <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ;
1991 [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
1993 [<span class="optional"> search { <em class="replaceable"><code>domain_name</code></em> ; [<span class="optional"> <em class="replaceable"><code>domain_name</code></em> ; ... </span>] }; </span>]
1995 };
1996 </pre>
1997 </div>
2000 <a name="id2577554"></a><span><strong class="command">lwres</strong></span> Statement Definition and Usage</h3></div></div></div>
2001 <p>
2003 name
2004 server to also act as a lightweight resolver server. (See
2005 <a href="Bv9ARM.ch05.html#lwresd" title="Running a Resolver Daemon">the section called “Running a Resolver Daemon”</a>.) There may be multiple
2007 lightweight resolver servers with different properties.
2008 </p>
2009 <p>
2011 list of
2012 addresses (and ports) that this instance of a lightweight resolver
2013 daemon
2014 should accept requests on. If no port is specified, port 921 is
2015 used.
2016 If this statement is omitted, requests will be accepted on
2017 127.0.0.1,
2018 port 921.
2019 </p>
2020 <p>
2022 instance of a
2023 lightweight resolver daemon to a view in the DNS namespace, so that
2024 the
2025 response will be constructed in the same manner as a normal DNS
2026 query
2027 matching this view. If this statement is omitted, the default view
2028 is
2029 used, and if there is no default view, an error is triggered.
2030 </p>
2031 <p>
2033 the
2036 list of domains
2037 which are appended to relative names in queries.
2038 </p>
2039 <p>
2041 the
2044 minimum
2045 number of dots in a relative domain name that should result in an
2046 exact match lookup before search path elements are appended.
2047 </p>
2048 </div>
2051 <a name="id2577686"></a><span><strong class="command">masters</strong></span> Statement Grammar</h3></div></div></div>
2053 <span><strong class="command">masters</strong></span> <em class="replaceable"><code>name</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] { ( <em class="replaceable"><code>masters_list</code></em> |
2054 <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] [<span class="optional">key <em class="replaceable"><code>key</code></em></span>] ) ; [<span class="optional">...</span>] };
2055 </pre>
2056 </div>
2059 <a name="id2577730"></a><span><strong class="command">masters</strong></span> Statement Definition and
2060 Usage</h3></div></div></div>
2062 lists allow for a common set of masters to be easily used by
2063 multiple stub and slave zones.
2064 </p>
2065 </div>
2068 <a name="id2577745"></a><span><strong class="command">options</strong></span> Statement Grammar</h3></div></div></div>
2069 <p>
2072 </p>
2074 [<span class="optional"> attach-cache <em class="replaceable"><code>cache_name</code></em>; </span>]
2075 [<span class="optional"> version <em class="replaceable"><code>version_string</code></em>; </span>]
2076 [<span class="optional"> hostname <em class="replaceable"><code>hostname_string</code></em>; </span>]
2077 [<span class="optional"> server-id <em class="replaceable"><code>server_id_string</code></em>; </span>]
2078 [<span class="optional"> directory <em class="replaceable"><code>path_name</code></em>; </span>]
2079 [<span class="optional"> key-directory <em class="replaceable"><code>path_name</code></em>; </span>]
2080 [<span class="optional"> named-xfer <em class="replaceable"><code>path_name</code></em>; </span>]
2081 [<span class="optional"> tkey-gssapi-credential <em class="replaceable"><code>principal</code></em>; </span>]
2082 [<span class="optional"> tkey-domain <em class="replaceable"><code>domainname</code></em>; </span>]
2083 [<span class="optional"> tkey-dhkey <em class="replaceable"><code>key_name</code></em> <em class="replaceable"><code>key_tag</code></em>; </span>]
2084 [<span class="optional"> cache-file <em class="replaceable"><code>path_name</code></em>; </span>]
2085 [<span class="optional"> dump-file <em class="replaceable"><code>path_name</code></em>; </span>]
2086 [<span class="optional"> bindkeys-file <em class="replaceable"><code>path_name</code></em>; </span>]
2087 [<span class="optional"> memstatistics <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2088 [<span class="optional"> memstatistics-file <em class="replaceable"><code>path_name</code></em>; </span>]
2089 [<span class="optional"> pid-file <em class="replaceable"><code>path_name</code></em>; </span>]
2090 [<span class="optional"> recursing-file <em class="replaceable"><code>path_name</code></em>; </span>]
2091 [<span class="optional"> statistics-file <em class="replaceable"><code>path_name</code></em>; </span>]
2092 [<span class="optional"> zone-statistics <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2093 [<span class="optional"> auth-nxdomain <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2094 [<span class="optional"> deallocate-on-exit <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2095 [<span class="optional"> dialup <em class="replaceable"><code>dialup_option</code></em>; </span>]
2096 [<span class="optional"> fake-iquery <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2097 [<span class="optional"> fetch-glue <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2098 [<span class="optional"> flush-zones-on-shutdown <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2099 [<span class="optional"> has-old-clients <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2100 [<span class="optional"> host-statistics <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2101 [<span class="optional"> host-statistics-max <em class="replaceable"><code>number</code></em>; </span>]
2102 [<span class="optional"> minimal-responses <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2103 [<span class="optional"> multiple-cnames <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2104 [<span class="optional"> notify <em class="replaceable"><code>yes_or_no</code></em> | <em class="replaceable"><code>explicit</code></em> | <em class="replaceable"><code>master-only</code></em>; </span>]
2105 [<span class="optional"> recursion <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2106 [<span class="optional"> rfc2308-type1 <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2107 [<span class="optional"> use-id-pool <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2108 [<span class="optional"> maintain-ixfr-base <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2109 [<span class="optional"> ixfr-from-differences (<em class="replaceable"><code>yes_or_no</code></em> | <code class="constant">master</code> | <code class="constant">slave</code>); </span>]
2110 [<span class="optional"> dnssec-enable <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2111 [<span class="optional"> dnssec-validation <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2113 <em class="replaceable"><code>domain</code></em> trust-anchor <em class="replaceable"><code>domain</code></em> ); </span>]
2114 [<span class="optional"> dnssec-must-be-secure <em class="replaceable"><code>domain yes_or_no</code></em>; </span>]
2115 [<span class="optional"> dnssec-accept-expired <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2116 [<span class="optional"> forward ( <em class="replaceable"><code>only</code></em> | <em class="replaceable"><code>first</code></em> ); </span>]
2117 [<span class="optional"> forwarders { [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
2118 [<span class="optional"> dual-stack-servers [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] {
2119 ( <em class="replaceable"><code>domain_name</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] |
2120 <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ) ;
2121 ... }; </span>]
2122 [<span class="optional"> check-names ( <em class="replaceable"><code>master</code></em> | <em class="replaceable"><code>slave</code></em> | <em class="replaceable"><code>response</code></em> )
2123 ( <em class="replaceable"><code>warn</code></em> | <em class="replaceable"><code>fail</code></em> | <em class="replaceable"><code>ignore</code></em> ); </span>]
2124 [<span class="optional"> check-dup-records ( <em class="replaceable"><code>warn</code></em> | <em class="replaceable"><code>fail</code></em> | <em class="replaceable"><code>ignore</code></em> ); </span>]
2125 [<span class="optional"> check-mx ( <em class="replaceable"><code>warn</code></em> | <em class="replaceable"><code>fail</code></em> | <em class="replaceable"><code>ignore</code></em> ); </span>]
2126 [<span class="optional"> check-wildcard <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2127 [<span class="optional"> check-integrity <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2128 [<span class="optional"> check-mx-cname ( <em class="replaceable"><code>warn</code></em> | <em class="replaceable"><code>fail</code></em> | <em class="replaceable"><code>ignore</code></em> ); </span>]
2129 [<span class="optional"> check-srv-cname ( <em class="replaceable"><code>warn</code></em> | <em class="replaceable"><code>fail</code></em> | <em class="replaceable"><code>ignore</code></em> ); </span>]
2130 [<span class="optional"> check-sibling <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2131 [<span class="optional"> allow-notify { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2132 [<span class="optional"> allow-query { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2133 [<span class="optional"> allow-query-on { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2134 [<span class="optional"> allow-query-cache { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2135 [<span class="optional"> allow-query-cache-on { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2136 [<span class="optional"> allow-transfer { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2137 [<span class="optional"> allow-recursion { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2138 [<span class="optional"> allow-recursion-on { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2139 [<span class="optional"> allow-update { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2140 [<span class="optional"> allow-update-forwarding { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2141 [<span class="optional"> update-check-ksk <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2142 [<span class="optional"> dnssec-dnskey-kskonly <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2143 [<span class="optional"> dnssec-secure-to-insecure <em class="replaceable"><code>yes_or_no</code></em> ;</span>]
2144 [<span class="optional"> try-tcp-refresh <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2145 [<span class="optional"> allow-v6-synthesis { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2146 [<span class="optional"> blackhole { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2147 [<span class="optional"> use-v4-udp-ports { <em class="replaceable"><code>port_list</code></em> }; </span>]
2148 [<span class="optional"> avoid-v4-udp-ports { <em class="replaceable"><code>port_list</code></em> }; </span>]
2149 [<span class="optional"> use-v6-udp-ports { <em class="replaceable"><code>port_list</code></em> }; </span>]
2150 [<span class="optional"> avoid-v6-udp-ports { <em class="replaceable"><code>port_list</code></em> }; </span>]
2151 [<span class="optional"> listen-on [<span class="optional"> port <em class="replaceable"><code>ip_port</code></em> </span>] { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2152 [<span class="optional"> listen-on-v6 [<span class="optional"> port <em class="replaceable"><code>ip_port</code></em> </span>] { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
2153 [<span class="optional"> query-source ( ( <em class="replaceable"><code>ip4_addr</code></em> | <em class="replaceable"><code>*</code></em> )
2154 [<span class="optional"> port ( <em class="replaceable"><code>ip_port</code></em> | <em class="replaceable"><code>*</code></em> ) </span>] |
2155 [<span class="optional"> address ( <em class="replaceable"><code>ip4_addr</code></em> | <em class="replaceable"><code>*</code></em> ) </span>]
2156 [<span class="optional"> port ( <em class="replaceable"><code>ip_port</code></em> | <em class="replaceable"><code>*</code></em> ) </span>] ) ; </span>]
2157 [<span class="optional"> query-source-v6 ( ( <em class="replaceable"><code>ip6_addr</code></em> | <em class="replaceable"><code>*</code></em> )
2158 [<span class="optional"> port ( <em class="replaceable"><code>ip_port</code></em> | <em class="replaceable"><code>*</code></em> ) </span>] |
2159 [<span class="optional"> address ( <em class="replaceable"><code>ip6_addr</code></em> | <em class="replaceable"><code>*</code></em> ) </span>]
2160 [<span class="optional"> port ( <em class="replaceable"><code>ip_port</code></em> | <em class="replaceable"><code>*</code></em> ) </span>] ) ; </span>]
2161 [<span class="optional"> use-queryport-pool <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2162 [<span class="optional"> queryport-pool-ports <em class="replaceable"><code>number</code></em>; </span>]
2163 [<span class="optional"> queryport-pool-updateinterval <em class="replaceable"><code>number</code></em>; </span>]
2164 [<span class="optional"> max-transfer-time-in <em class="replaceable"><code>number</code></em>; </span>]
2165 [<span class="optional"> max-transfer-time-out <em class="replaceable"><code>number</code></em>; </span>]
2166 [<span class="optional"> max-transfer-idle-in <em class="replaceable"><code>number</code></em>; </span>]
2167 [<span class="optional"> max-transfer-idle-out <em class="replaceable"><code>number</code></em>; </span>]
2168 [<span class="optional"> tcp-clients <em class="replaceable"><code>number</code></em>; </span>]
2169 [<span class="optional"> reserved-sockets <em class="replaceable"><code>number</code></em>; </span>]
2170 [<span class="optional"> recursive-clients <em class="replaceable"><code>number</code></em>; </span>]
2171 [<span class="optional"> serial-query-rate <em class="replaceable"><code>number</code></em>; </span>]
2172 [<span class="optional"> serial-queries <em class="replaceable"><code>number</code></em>; </span>]
2173 [<span class="optional"> tcp-listen-queue <em class="replaceable"><code>number</code></em>; </span>]
2174 [<span class="optional"> transfer-format <em class="replaceable"><code>( one-answer | many-answers )</code></em>; </span>]
2175 [<span class="optional"> transfers-in <em class="replaceable"><code>number</code></em>; </span>]
2176 [<span class="optional"> transfers-out <em class="replaceable"><code>number</code></em>; </span>]
2177 [<span class="optional"> transfers-per-ns <em class="replaceable"><code>number</code></em>; </span>]
2178 [<span class="optional"> transfer-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
2179 [<span class="optional"> transfer-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
2180 [<span class="optional"> alt-transfer-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
2181 [<span class="optional"> alt-transfer-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>)
2182 [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
2183 [<span class="optional"> use-alt-transfer-source <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2184 [<span class="optional"> notify-delay <em class="replaceable"><code>seconds</code></em> ; </span>]
2185 [<span class="optional"> notify-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
2186 [<span class="optional"> notify-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
2187 [<span class="optional"> notify-to-soa <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2188 [<span class="optional"> also-notify { <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ;
2189 [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
2190 [<span class="optional"> max-ixfr-log-size <em class="replaceable"><code>number</code></em>; </span>]
2191 [<span class="optional"> max-journal-size <em class="replaceable"><code>size_spec</code></em>; </span>]
2192 [<span class="optional"> coresize <em class="replaceable"><code>size_spec</code></em> ; </span>]
2193 [<span class="optional"> datasize <em class="replaceable"><code>size_spec</code></em> ; </span>]
2195 [<span class="optional"> stacksize <em class="replaceable"><code>size_spec</code></em> ; </span>]
2196 [<span class="optional"> cleaning-interval <em class="replaceable"><code>number</code></em>; </span>]
2197 [<span class="optional"> heartbeat-interval <em class="replaceable"><code>number</code></em>; </span>]
2198 [<span class="optional"> interface-interval <em class="replaceable"><code>number</code></em>; </span>]
2199 [<span class="optional"> statistics-interval <em class="replaceable"><code>number</code></em>; </span>]
2200 [<span class="optional"> topology { <em class="replaceable"><code>address_match_list</code></em> }</span>];
2201 [<span class="optional"> sortlist { <em class="replaceable"><code>address_match_list</code></em> }</span>];
2202 [<span class="optional"> rrset-order { <em class="replaceable"><code>order_spec</code></em> ; [<span class="optional"> <em class="replaceable"><code>order_spec</code></em> ; ... </span>] </span>] };
2204 [<span class="optional"> max-ncache-ttl <em class="replaceable"><code>number</code></em>; </span>]
2205 [<span class="optional"> max-cache-ttl <em class="replaceable"><code>number</code></em>; </span>]
2206 [<span class="optional"> sig-validity-interval <em class="replaceable"><code>number</code></em> [<span class="optional"><em class="replaceable"><code>number</code></em></span>] ; </span>]
2207 [<span class="optional"> sig-signing-nodes <em class="replaceable"><code>number</code></em> ; </span>]
2208 [<span class="optional"> sig-signing-signatures <em class="replaceable"><code>number</code></em> ; </span>]
2209 [<span class="optional"> sig-signing-type <em class="replaceable"><code>number</code></em> ; </span>]
2211 [<span class="optional"> use-ixfr <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2212 [<span class="optional"> provide-ixfr <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2213 [<span class="optional"> request-ixfr <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2214 [<span class="optional"> treat-cr-as-space <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2215 [<span class="optional"> min-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
2216 [<span class="optional"> max-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
2217 [<span class="optional"> min-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
2218 [<span class="optional"> max-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
2220 [<span class="optional"> additional-from-auth <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2221 [<span class="optional"> additional-from-cache <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2222 [<span class="optional"> random-device <em class="replaceable"><code>path_name</code></em> ; </span>]
2223 [<span class="optional"> max-cache-size <em class="replaceable"><code>size_spec</code></em> ; </span>]
2224 [<span class="optional"> match-mapped-addresses <em class="replaceable"><code>yes_or_no</code></em>; </span>]
2225 [<span class="optional"> filter-aaaa-on-v4 ( <em class="replaceable"><code>yes_or_no</code></em> | <em class="replaceable"><code>break-dnssec</code></em> ); </span>]
2226 [<span class="optional"> preferred-glue ( <em class="replaceable"><code>A</code></em> | <em class="replaceable"><code>AAAA</code></em> | <em class="replaceable"><code>NONE</code></em> ); </span>]
2227 [<span class="optional"> edns-udp-size <em class="replaceable"><code>number</code></em>; </span>]
2228 [<span class="optional"> max-udp-size <em class="replaceable"><code>number</code></em>; </span>]
2229 [<span class="optional"> root-delegation-only [<span class="optional"> exclude { <em class="replaceable"><code>namelist</code></em> } </span>] ; </span>]
2230 [<span class="optional"> querylog <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2231 [<span class="optional"> disable-algorithms <em class="replaceable"><code>domain</code></em> { <em class="replaceable"><code>algorithm</code></em>;
2232 [<span class="optional"> <em class="replaceable"><code>algorithm</code></em>; </span>] }; </span>]
2233 [<span class="optional"> acache-enable <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2234 [<span class="optional"> acache-cleaning-interval <em class="replaceable"><code>number</code></em>; </span>]
2235 [<span class="optional"> max-acache-size <em class="replaceable"><code>size_spec</code></em> ; </span>]
2236 [<span class="optional"> clients-per-query <em class="replaceable"><code>number</code></em> ; </span>]
2237 [<span class="optional"> max-clients-per-query <em class="replaceable"><code>number</code></em> ; </span>]
2238 [<span class="optional"> masterfile-format (<code class="constant">text</code>|<code class="constant">raw</code>) ; </span>]
2239 [<span class="optional"> empty-server <em class="replaceable"><code>name</code></em> ; </span>]
2240 [<span class="optional"> empty-contact <em class="replaceable"><code>name</code></em> ; </span>]
2241 [<span class="optional"> empty-zones-enable <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2242 [<span class="optional"> disable-empty-zone <em class="replaceable"><code>zone_name</code></em> ; </span>]
2243 [<span class="optional"> zero-no-soa-ttl <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2244 [<span class="optional"> zero-no-soa-ttl-cache <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
2245 [<span class="optional"> deny-answer-addresses { <em class="replaceable"><code>address_match_list</code></em> } [<span class="optional"> except-from { <em class="replaceable"><code>namelist</code></em> } </span>];</span>]
2246 [<span class="optional"> deny-answer-aliases { <em class="replaceable"><code>namelist</code></em> } [<span class="optional"> except-from { <em class="replaceable"><code>namelist</code></em> } </span>];</span>]
2247 };
2248 </pre>
2249 </div>
2252 <a name="options"></a><span><strong class="command">options</strong></span> Statement Definition and
2253 Usage</h3></div></div></div>
2254 <p>
2256 options
2258 may appear only
2259 once in a configuration file. If there is no <span><strong class="command">options</strong></span>
2260 statement, an options block with each option set to its default will
2261 be used.
2262 </p>
2265 <dd>
2266 <p>
2267 Allows multiple views to share a single cache
2268 database.
2269 Each view has its own cache database by default, but
2270 if multiple views have the same operational policy
2271 for name resolution and caching, those views can
2272 share a single cache to save memory and possibly
2273 improve resolution efficiency by using this option.
2274 </p>
2275 <p>
2278 statements, in which case it overrides the
2280 </p>
2281 <p>
2283 the cache to be shared.
2285 views which are supposed to share a cache, it
2286 creates a cache with the specified name for the
2287 first view of these sharing views.
2288 The rest of the views will simply refer to the
2289 already created cache.
2290 </p>
2291 <p>
2292 One common configuration to share a cache would be to
2293 allow all views to share a single cache.
2294 This can be done by specifying
2296 option with an arbitrary name.
2297 </p>
2298 <p>
2299 Another possible operation is to allow a subset of
2300 all views to share a cache while the others to
2301 retain their own caches.
2302 For example, if there are three views A, B, and C,
2303 and only A and B should share a cache, specify the
2305 B)'s option, referring to the other view name:
2306 </p>
2308 view "A" {
2309 // this view has its own cache
2310 ...
2311 };
2312 view "B" {
2313 // this view refers to A's cache
2314 attach-cache "A";
2315 };
2316 view "C" {
2317 // this view has its own cache
2318 ...
2319 };
2320 </pre>
2321 <p>
2322 Views that share a cache must have the same policy
2323 on configurable parameters that may affect caching.
2324 The current implementation requires the following
2325 configurable options be consistent among these
2326 views:
2335 </p>
2336 <p>
2337 Note that there may be other parameters that may
2338 cause confusion if they are inconsistent for
2339 different views that share a single cache.
2340 For example, if these views define different sets of
2341 forwarders that can return different answers for the
2342 same question, sharing the answer does not make
2343 sense or could even be harmful.
2344 It is administrator's responsibility to ensure
2345 configuration differences in different views do
2346 not cause disruption with a shared cache.
2347 </p>
2348 </dd>
2350 <dd><p>
2351 The working directory of the server.
2352 Any non-absolute pathnames in the configuration file will be
2353 taken
2354 as relative to this directory. The default location for most
2355 server
2357 is this directory.
2358 If a directory is not specified, the working directory
2360 which the server
2361 was started. The directory specified should be an absolute
2362 path.
2363 </p></dd>
2365 <dd><p>
2366 When performing dynamic update of secure zones, the
2367 directory where the public and private DNSSEC key files
2368 should be found, if different than the current working
2369 directory. (Note that this option has no effect on the
2370 paths for files containing non-DNSSEC keys such as
2374 </p></dd>
2376 <dd><p>
2382 its functionality is built into the name server.
2383 </p></dd>
2384 <dt><span class="term"><span><strong class="command">tkey-gssapi-credential</strong></span></span></dt>
2385 <dd><p>
2386 The security credential with which the server should
2387 authenticate keys requested by the GSS-TSIG protocol.
2388 Currently only Kerberos 5 authentication is available
2389 and the credential is a Kerberos principal which
2390 the server can acquire through the default system
2392 Normally this principal is of the form
2393 "<strong class="userinput"><code>dns/</code></strong><code class="varname">server.domain</code>".
2395 must also be set.
2396 </p></dd>
2398 <dd><p>
2399 The domain appended to the names of all shared keys
2402 it may or may not specify the desired name for the
2403 key. If present, the name of the shared key will
2409 should be the server's domain name, or an otherwise
2410 non-existent subdomain like
2412 using GSS-TSIG, this variable must be defined.
2413 </p></dd>
2415 <dd><p>
2416 The Diffie-Hellman key used by the server
2417 to generate shared keys with clients using the Diffie-Hellman
2418 mode
2420 able to load the
2421 public and private keys from files in the working directory.
2422 In
2423 most cases, the keyname should be the server's host name.
2424 </p></dd>
2426 <dd><p>
2427 This is for testing only. Do not use.
2428 </p></dd>
2430 <dd><p>
2431 The pathname of the file the server dumps
2432 the database to when instructed to do so with
2435 </p></dd>
2436 <dt><span class="term"><span><strong class="command">memstatistics-file</strong></span></span></dt>
2437 <dd><p>
2438 The pathname of the file the server writes memory
2439 usage statistics to on exit. If not specified,
2441 </p></dd>
2443 <dd><p>
2444 The pathname of the file the server writes its process ID
2445 in. If not specified, the default is
2447 The PID file is used by programs that want to send signals to
2448 the running
2449 name server. Specifying <span><strong class="command">pid-file none</strong></span> disables the
2450 use of a PID file — no file will be written and any
2452 is a keyword, not a filename, and therefore is not enclosed
2453 in
2454 double quotes.
2455 </p></dd>
2456 <dt><span class="term"><span><strong class="command">recursing-file</strong></span></span></dt>
2457 <dd><p>
2458 The pathname of the file the server dumps
2459 the queries that are currently recursing when instructed
2462 </p></dd>
2463 <dt><span class="term"><span><strong class="command">statistics-file</strong></span></span></dt>
2464 <dd><p>
2465 The pathname of the file the server appends statistics
2468 server's current directory. The format of the file is
2469 described
2470 in <a href="Bv9ARM.ch06.html#statsfile" title="The Statistics File">the section called “The Statistics File”</a>.
2471 </p></dd>
2473 <dd><p>
2474 The pathname of a file to override the built-in trusted
2477 for details. If not specified, the default is
2479 </p></dd>
2480 <dt><span class="term"><span><strong class="command">session-keyfile</strong></span></span></dt>
2481 <dd><p>
2482 The pathname of the file into which to write a TSIG
2486 (See <a href="Bv9ARM.ch06.html#dynamic_update_policies" title="Dynamic Update Policies">the section called “Dynamic Update Policies”</a>, and in
2487 particular the discussion of the
2490 information about this feature.)
2491 </p></dd>
2492 <dt><span class="term"><span><strong class="command">session-keyname</strong></span></span></dt>
2493 <dd><p>
2494 The key name to use for the TSIG session key.
2495 If not specified, the default is "local-ddns".
2496 </p></dd>
2497 <dt><span class="term"><span><strong class="command">session-keyalg</strong></span></span></dt>
2498 <dd><p>
2499 The algorithm to use for the TSIG session key.
2500 Valid values are hmac-sha1, hmac-sha224, hmac-sha256,
2501 hmac-sha384, hmac-sha512 and hmac-md5. If not
2502 specified, the default is hmac-sha256.
2503 </p></dd>
2504 <dt><span class="term"><span><strong class="command">session-keyfile</strong></span></span></dt>
2505 <dd><p>
2506 The pathname of the file into which to write a session TSIG
2510 details on this feature.)
2511 </p></dd>
2513 <dd><p>
2514 The UDP/TCP port number the server uses for
2515 receiving and sending DNS protocol traffic.
2516 The default is 53. This option is mainly intended for server
2517 testing;
2518 a server using a port other than 53 will not be able to
2519 communicate with
2520 the global DNS.
2521 </p></dd>
2523 <dd><p>
2524 The source of entropy to be used by the server. Entropy is
2525 primarily needed
2526 for DNSSEC operations, such as TKEY transactions and dynamic
2527 update of signed
2528 zones. This options specifies the device (or file) from which
2529 to read
2530 entropy. If this is a file, operations requiring entropy will
2531 fail when the
2532 file has been exhausted. If not specified, the default value
2533 is
2535 (or equivalent) when present, and none otherwise. The
2537 effect during
2538 the initial configuration load at server startup time and
2539 is ignored on subsequent reloads.
2540 </p></dd>
2541 <dt><span class="term"><span><strong class="command">preferred-glue</strong></span></span></dt>
2542 <dd><p>
2543 If specified, the listed type (A or AAAA) will be emitted
2544 before other glue
2545 in the additional section of a query response.
2546 The default is not to prefer any type (NONE).
2547 </p></dd>
2548 <dt>
2549 <a name="root_delegation_only"></a><span class="term"><span><strong class="command">root-delegation-only</strong></span></span>
2550 </dt>
2551 <dd>
2552 <p>
2553 Turn on enforcement of delegation-only in TLDs
2554 (top level domains) and root zones with an optional
2555 exclude list.
2556 </p>
2557 <p>
2558 DS queries are expected to be made to and be answered by
2559 delegation only zones. Such queries and responses are
2560 treated as an exception to delegation-only processing
2561 and are not converted to NXDOMAIN responses provided
2562 a CNAME is not discovered at the query name.
2563 </p>
2564 <p>
2565 If a delegation only zone server also serves a child
2566 zone it is not always possible to determine whether
2567 an answer comes from the delegation only zone or the
2568 child zone. SOA NS and DNSKEY records are apex
2569 only records and a matching response that contains
2570 these records or DS is treated as coming from a
2571 child zone. RRSIG records are also examined to see
2572 if they are signed by a child zone or not. The
2573 authority section is also examined to see if there
2574 is evidence that the answer is from the child zone.
2575 Answers that are determined to be from a child zone
2576 are not converted to NXDOMAIN responses. Despite
2577 all these checks there is still a possibility of
2578 false negatives when a child zone is being served.
2579 </p>
2580 <p>
2581 Similarly false positives can arise from empty nodes
2582 (no records at the name) in the delegation only zone
2583 when the query type is not ANY.
2584 </p>
2585 <p>
2588 </p>
2590 options {
2592 };
2593 </pre>
2594 </dd>
2595 <dt><span class="term"><span><strong class="command">disable-algorithms</strong></span></span></dt>
2596 <dd><p>
2597 Disable the specified DNSSEC algorithms at and below the
2598 specified name.
2600 statements are allowed.
2601 Only the most specific will be applied.
2602 </p></dd>
2603 <dt><span class="term"><span><strong class="command">dnssec-lookaside</strong></span></span></dt>
2604 <dd>
2605 <p>
2607 validator with an alternate method to validate DNSKEY
2608 records at the top of a zone. When a DNSKEY is at or
2609 below a domain specified by the deepest
2611 validation has left the key untrusted, the trust-anchor
2612 will be appended to the key name and a DLV record will be
2613 looked up to see if it can validate the key. If the DLV
2614 record validates a DNSKEY (similarly to the way a DS
2615 record does) the DNSKEY RRset is deemed to be trusted.
2616 </p>
2617 <p>
2620 values for the DLV domain and trust anchor will be
2621 used, along with a built-in key for validation.
2622 </p>
2623 <p>
2624 The default DLV key is stored in the file
2630 current as of the release date. If the DLV key expires, a
2633 </p>
2634 <p>
2636 not found, the current key is also compiled in to
2639 to be recompiled with a new key when the DLV key expires.)
2640 </p>
2641 <p>
2643 locally-configured keys is possible, but not
2644 recommended, as the file will be overwritten whenever
2646 </p>
2647 </dd>
2648 <dt><span class="term"><span><strong class="command">dnssec-must-be-secure</strong></span></span></dt>
2649 <dd><p>
2650 Specify hierarchies which must be or may not be secure
2654 DNSSEC validation applies allowing for insecure answers to
2655 be accepted. The specified domain must be under a
2659 </p></dd>
2660 </dl></div>
2666 <dd><p>
2667 If <strong class="userinput"><code>yes</code></strong>, then the <span><strong class="command">AA</strong></span> bit
2668 is always set on NXDOMAIN responses, even if the server is
2669 not actually
2671 this is
2673 are using very old DNS software, you
2675 </p></dd>
2676 <dt><span class="term"><span><strong class="command">deallocate-on-exit</strong></span></span></dt>
2677 <dd><p>
2679 8 to enable checking
2680 for memory leaks on exit. <acronym class="acronym">BIND</acronym> 9 ignores the option and always performs
2681 the checks.
2682 </p></dd>
2684 <dd><p>
2685 Write memory statistics to the file specified by
2688 '-m record' is specified on the command line in
2690 </p></dd>
2692 <dd>
2693 <p>
2695 server treats all zones as if they are doing zone transfers
2696 across
2697 a dial-on-demand dialup link, which can be brought up by
2698 traffic
2699 originating from this server. This has different effects
2700 according
2701 to zone type and concentrates the zone maintenance so that
2702 it all
2703 happens in a short interval, once every <span><strong class="command">heartbeat-interval</strong></span> and
2704 hopefully during the one call. It also suppresses some of
2705 the normal
2707 </p>
2708 <p>
2713 option.
2714 </p>
2715 <p>
2716 If the zone is a master zone, then the server will send out a
2717 NOTIFY
2718 request to all the slaves (default). This should trigger the
2719 zone serial
2720 number check in the slave (providing it supports NOTIFY)
2721 allowing the slave
2722 to verify the zone while the connection is active.
2723 The set of servers to which NOTIFY is sent can be controlled
2724 by
2725 <span><strong class="command">notify</strong></span> and <span><strong class="command">also-notify</strong></span>.
2726 </p>
2727 <p>
2728 If the
2729 zone is a slave or stub zone, then the server will suppress
2730 the regular
2731 "zone up to date" (refresh) queries and only perform them
2732 when the
2734 addition to sending
2735 NOTIFY requests.
2736 </p>
2737 <p>
2738 Finer control can be achieved by using
2740 messages,
2742 messages and
2744 which suppresses normal refresh processing and sends refresh
2745 queries
2747 expires, and
2749 refresh
2750 processing.
2751 </p>
2753 <colgroup>
2754 <col>
2755 <col>
2756 <col>
2757 <col>
2758 </colgroup>
2759 <tbody>
2760 <tr>
2761 <td>
2762 <p>
2763 dialup mode
2764 </p>
2765 </td>
2766 <td>
2767 <p>
2768 normal refresh
2769 </p>
2770 </td>
2771 <td>
2772 <p>
2773 heart-beat refresh
2774 </p>
2775 </td>
2776 <td>
2777 <p>
2778 heart-beat notify
2779 </p>
2780 </td>
2781 </tr>
2782 <tr>
2783 <td>
2785 </td>
2786 <td>
2787 <p>
2788 yes
2789 </p>
2790 </td>
2791 <td>
2792 <p>
2793 no
2794 </p>
2795 </td>
2796 <td>
2797 <p>
2798 no
2799 </p>
2800 </td>
2801 </tr>
2802 <tr>
2803 <td>
2805 </td>
2806 <td>
2807 <p>
2808 no
2809 </p>
2810 </td>
2811 <td>
2812 <p>
2813 yes
2814 </p>
2815 </td>
2816 <td>
2817 <p>
2818 yes
2819 </p>
2820 </td>
2821 </tr>
2822 <tr>
2823 <td>
2825 </td>
2826 <td>
2827 <p>
2828 yes
2829 </p>
2830 </td>
2831 <td>
2832 <p>
2833 no
2834 </p>
2835 </td>
2836 <td>
2837 <p>
2838 yes
2839 </p>
2840 </td>
2841 </tr>
2842 <tr>
2843 <td>
2845 </td>
2846 <td>
2847 <p>
2848 no
2849 </p>
2850 </td>
2851 <td>
2852 <p>
2853 yes
2854 </p>
2855 </td>
2856 <td>
2857 <p>
2858 no
2859 </p>
2860 </td>
2861 </tr>
2862 <tr>
2863 <td>
2865 </td>
2866 <td>
2867 <p>
2868 no
2869 </p>
2870 </td>
2871 <td>
2872 <p>
2873 no
2874 </p>
2875 </td>
2876 <td>
2877 <p>
2878 no
2879 </p>
2880 </td>
2881 </tr>
2882 <tr>
2883 <td>
2885 </td>
2886 <td>
2887 <p>
2888 no
2889 </p>
2890 </td>
2891 <td>
2892 <p>
2893 no
2894 </p>
2895 </td>
2896 <td>
2897 <p>
2898 yes
2899 </p>
2900 </td>
2901 </tr>
2902 </tbody>
2903 </table></div>
2904 <p>
2905 Note that normal NOTIFY processing is not affected by
2907 </p>
2908 </dd>
2910 <dd><p>
2912 enabled simulating the obsolete DNS query type
2914 IQUERY simulation.
2915 </p></dd>
2917 <dd><p>
2918 This option is obsolete.
2920 caused the server to attempt to fetch glue resource records
2921 it
2922 didn't have when constructing the additional
2923 data section of a response. This is now considered a bad
2924 idea
2925 and BIND 9 never does it.
2926 </p></dd>
2927 <dt><span class="term"><span><strong class="command">flush-zones-on-shutdown</strong></span></span></dt>
2928 <dd><p>
2929 When the nameserver exits due receiving SIGTERM,
2930 flush or do not flush any pending zone writes. The default
2931 is
2932 <span><strong class="command">flush-zones-on-shutdown</strong></span> <strong class="userinput"><code>no</code></strong>.
2933 </p></dd>
2934 <dt><span class="term"><span><strong class="command">has-old-clients</strong></span></span></dt>
2935 <dd><p>
2936 This option was incorrectly implemented
2937 in <acronym class="acronym">BIND</acronym> 8, and is ignored by <acronym class="acronym">BIND</acronym> 9.
2938 To achieve the intended effect
2939 of
2940 <span><strong class="command">has-old-clients</strong></span> <strong class="userinput"><code>yes</code></strong>, specify
2941 the two separate options <span><strong class="command">auth-nxdomain</strong></span> <strong class="userinput"><code>yes</code></strong>
2942 and <span><strong class="command">rfc2308-type1</strong></span> <strong class="userinput"><code>no</code></strong> instead.
2943 </p></dd>
2944 <dt><span class="term"><span><strong class="command">host-statistics</strong></span></span></dt>
2945 <dd><p>
2946 In BIND 8, this enables keeping of
2947 statistics for every host that the name server interacts
2948 with.
2949 Not implemented in BIND 9.
2950 </p></dd>
2951 <dt><span class="term"><span><strong class="command">maintain-ixfr-base</strong></span></span></dt>
2952 <dd><p>
2955 determine whether a transaction log was
2956 kept for Incremental Zone Transfer. <acronym class="acronym">BIND</acronym> 9 maintains a transaction
2957 log whenever possible. If you need to disable outgoing
2958 incremental zone
2959 transfers, use <span><strong class="command">provide-ixfr</strong></span> <strong class="userinput"><code>no</code></strong>.
2960 </p></dd>
2961 <dt><span class="term"><span><strong class="command">minimal-responses</strong></span></span></dt>
2962 <dd><p>
2964 responses the server will only add records to the authority
2965 and additional data sections when they are required (e.g.
2966 delegations, negative responses). This may improve the
2967 performance of the server.
2969 </p></dd>
2970 <dt><span class="term"><span><strong class="command">multiple-cnames</strong></span></span></dt>
2971 <dd><p>
2973 a domain name to have multiple CNAME records in violation of
2975 always strictly enforces the CNAME rules both in master
2976 files and dynamic updates.
2977 </p></dd>
2979 <dd>
2980 <p>
2982 DNS NOTIFY messages are sent when a zone the server is
2983 authoritative for
2984 changes, see <a href="Bv9ARM.ch04.html#notify" title="Notify">the section called “Notify”</a>. The messages are
2985 sent to the
2986 servers listed in the zone's NS records (except the master
2987 server identified
2988 in the SOA MNAME field), and to any servers listed in the
2990 </p>
2991 <p>
2993 sent
2994 for master zones.
2996 to
2999 </p>
3000 <p>
3003 statement,
3004 in which case it overrides the <span><strong class="command">options notify</strong></span> statement.
3005 It would only be necessary to turn off this option if it
3006 caused slaves
3007 to crash.
3008 </p>
3009 </dd>
3011 <dd><p>
3013 in the NS RRset against the SOA MNAME. Normally a NOTIFY
3014 message is not sent to the SOA MNAME (SOA ORIGIN) as it is
3015 supposed to contain the name of the ultimate master.
3016 Sometimes, however, a slave is listed as the SOA MNAME in
3017 hidden master configurations and in that case you would
3018 want the ultimate master to still send NOTIFY messages to
3019 all the nameservers listed in the NS RRset.
3020 </p></dd>
3022 <dd><p>
3024 DNS query requests recursion, then the server will attempt
3025 to do
3026 all the work required to answer the query. If recursion is
3027 off
3028 and the server does not already know the answer, it will
3029 return a
3030 referral response. The default is
3033 clients from getting data from the server's cache; it only
3034 prevents new data from being cached as an effect of client
3035 queries.
3036 Caching may still occur as an effect the server's internal
3037 operation, such as NOTIFY address lookups.
3039 </p></dd>
3041 <dd>
3042 <p>
3044 cause the server to send NS records along with the SOA
3045 record for negative
3047 </p>
3050 <p>
3052 9.
3053 </p>
3054 </div>
3055 </dd>
3057 <dd><p>
3060 IDs from a pool.
3061 </p></dd>
3062 <dt><span class="term"><span><strong class="command">zone-statistics</strong></span></span></dt>
3063 <dd><p>
3065 statistical data on all zones (unless specifically turned
3066 off
3067 on a per-zone basis by specifying <span><strong class="command">zone-statistics no</strong></span>
3070 These statistics may be accessed
3072 dump them to the file listed
3074 also <a href="Bv9ARM.ch06.html#statsfile" title="The Statistics File">the section called “The Statistics File”</a>.
3075 </p></dd>
3077 <dd><p>
3079 If you need to disable IXFR to a particular server or
3080 servers, see
3082 in <a href="Bv9ARM.ch06.html#server_statement_definition_and_usage" title="server Statement Definition and
3083 Usage">the section called “<span><strong class="command">server</strong></span> Statement Definition and
3085 See also
3086 <a href="Bv9ARM.ch04.html#incremental_zone_transfers" title="Incremental Zone Transfers (IXFR)">the section called “Incremental Zone Transfers (IXFR)”</a>.
3087 </p></dd>
3089 <dd><p>
3090 See the description of
3092 <a href="Bv9ARM.ch06.html#server_statement_definition_and_usage" title="server Statement Definition and
3093 Usage">the section called “<span><strong class="command">server</strong></span> Statement Definition and
3095 </p></dd>
3097 <dd><p>
3098 See the description of
3100 <a href="Bv9ARM.ch06.html#server_statement_definition_and_usage" title="server Statement Definition and
3101 Usage">the section called “<span><strong class="command">server</strong></span> Statement Definition and
3103 </p></dd>
3104 <dt><span class="term"><span><strong class="command">treat-cr-as-space</strong></span></span></dt>
3105 <dd><p>
3107 8 to make
3108 the server treat carriage return ("<span><strong class="command">\r</strong></span>") characters the same way
3109 as a space or tab character,
3110 to facilitate loading of zone files on a UNIX system that
3111 were generated
3112 on an NT or DOS machine. In <acronym class="acronym">BIND</acronym> 9, both UNIX "<span><strong class="command">\n</strong></span>"
3114 are always accepted,
3115 and the option is ignored.
3116 </p></dd>
3117 <dt>
3118 <span class="term"><span><strong class="command">additional-from-auth</strong></span>, </span><span class="term"><span><strong class="command">additional-from-cache</strong></span></span>
3119 </dt>
3120 <dd>
3121 <p>
3122 These options control the behavior of an authoritative
3123 server when
3124 answering queries which have additional data, or when
3125 following CNAME
3126 and DNAME chains.
3127 </p>
3128 <p>
3130 (the default) and a
3131 query is being answered from authoritative data (a zone
3132 configured into the server), the additional data section of
3133 the
3134 reply will be filled in using data from other authoritative
3135 zones
3136 and from the cache. In some situations this is undesirable,
3137 such
3138 as when there is concern over the correctness of the cache,
3139 or
3140 in servers where slave zones may be added and modified by
3141 untrusted third parties. Also, avoiding
3142 the search for this additional data will speed up server
3143 operations
3144 at the possible expense of additional queries to resolve
3145 what would
3146 otherwise be provided in the additional section.
3147 </p>
3148 <p>
3149 For example, if a query asks for an MX record for host <code class="literal">foo.example.com</code>,
3150 and the record found is "<code class="literal">MX 10 mail.example.net</code>", normally the address
3151 records (A and AAAA) for <code class="literal">mail.example.net</code> will be provided as well,
3152 if known, even though they are not in the example.com zone.
3154 disables this behavior and makes
3155 the server only search for additional data in the zone it
3156 answers from.
3157 </p>
3158 <p>
3159 These options are intended for use in authoritative-only
3160 servers, or in authoritative-only views. Attempts to set
3162 specifying
3164 server to
3165 ignore the options and log a warning message.
3166 </p>
3167 <p>
3169 disables the use of the cache not only for additional data
3170 lookups
3171 but also when looking up the answer. This is usually the
3172 desired
3173 behavior in an authoritative-only server where the
3174 correctness of
3175 the cached data is an issue.
3176 </p>
3177 <p>
3178 When a name server is non-recursively queried for a name
3179 that is not
3180 below the apex of any served zone, it normally answers with
3181 an
3182 "upwards referral" to the root servers or the servers of
3183 some other
3184 known parent of the query name. Since the data in an
3185 upwards referral
3186 comes from the cache, the server will not be able to provide
3187 upwards
3189 has been specified. Instead, it will respond to such
3190 queries
3191 with REFUSED. This should not cause any problems since
3192 upwards referrals are not required for the resolution
3193 process.
3194 </p>
3195 </dd>
3196 <dt><span class="term"><span><strong class="command">match-mapped-addresses</strong></span></span></dt>
3197 <dd>
3198 <p>
3200 IPv4-mapped IPv6 address will match any address match
3201 list entries that match the corresponding IPv4 address.
3202 </p>
3203 <p>
3204 This option was introduced to work around a kernel quirk
3205 in some operating systems that causes IPv4 TCP
3206 connections, such as zone transfers, to be accepted on an
3207 IPv6 socket using mapped addresses. This caused address
3208 match lists designed for IPv4 to fail to match. However,
3210 internally. The use of this option is discouraged.
3211 </p>
3212 </dd>
3213 <dt><span class="term"><span><strong class="command">filter-aaaa-on-v4</strong></span></span></dt>
3214 <dd>
3215 <p>
3216 This option is only available when
3219 "configure" command line. It is intended to help the
3220 transition from IPv4 to IPv6 by not giving IPv6 addresses
3221 to DNS clients unless they have connections to the IPv6
3222 Internet. This is not recommended unless absolutely
3227 option.
3228 </p>
3229 <p>
3231 the DNS client is at an IPv4 address,
3232 and if the response does not include DNSSEC signatures,
3233 then all AAAA records are deleted from the response.
3234 This filtering applies to all responses and not only
3235 authoritative responses.
3236 </p>
3237 <p>
3239 then AAAA records are deleted even when dnssec is enabled.
3240 As suggested by the name, this makes the response not verify,
3241 because the DNSSEC protocol is designed detect deletions.
3242 </p>
3243 <p>
3244 This mechanism can erroneously cause other servers to
3245 not give AAAA records to their clients.
3246 A recursing server with both IPv6 and IPv4 network connections
3247 that queries an authoritative server using this mechanism
3248 via IPv4 will be denied AAAA records even if its client is
3249 using IPv6.
3250 </p>
3251 <p>
3252 This mechanism is applied to authoritative as well as
3253 non-authoritative records.
3254 A client using IPv4 that is not allowed recursion can
3255 erroneously be given AAAA records because the server is not
3256 allowed to check for A records.
3257 </p>
3258 <p>
3259 Some AAAA records are given to IPv4 clients in glue records.
3260 IPv4 clients that are servers can then erroneously
3261 answer requests for AAAA records received via IPv4.
3262 </p>
3263 </dd>
3264 <dt><span class="term"><span><strong class="command">ixfr-from-differences</strong></span></span></dt>
3265 <dd>
3266 <p>
3267 When <strong class="userinput"><code>yes</code></strong> and the server loads a new version of a master
3268 zone from its zone file or receives a new version of a slave
3269 file by a non-incremental zone transfer, it will compare
3270 the new version to the previous one and calculate a set
3271 of differences. The differences are then logged in the
3272 zone's journal file such that the changes can be transmitted
3273 to downstream slaves as an incremental zone transfer.
3274 </p>
3275 <p>
3276 By allowing incremental zone transfers to be used for
3277 non-dynamic zones, this option saves bandwidth at the
3278 expense of increased CPU and memory consumption at the
3279 master.
3280 In particular, if the new version of a zone is completely
3281 different from the previous one, the set of differences
3282 will be of a size comparable to the combined size of the
3283 old and new zone version, and the server will need to
3284 temporarily allocate memory to hold this complete
3285 difference set.
3286 </p>
3290 levels which causes
3294 It is off by default.
3295 </p>
3296 </dd>
3298 <dd><p>
3299 This should be set when you have multiple masters for a zone
3300 and the
3301 addresses refer to different machines. If <strong class="userinput"><code>yes</code></strong>, <span><strong class="command">named</strong></span> will
3302 not log
3303 when the serial number on the master is less than what <span><strong class="command">named</strong></span>
3304 currently
3306 </p></dd>
3308 <dd><p>
3309 Enable DNSSEC support in <span><strong class="command">named</strong></span>. Unless set to <strong class="userinput"><code>yes</code></strong>,
3312 </p></dd>
3313 <dt><span class="term"><span><strong class="command">dnssec-validation</strong></span></span></dt>
3314 <dd><p>
3319 </p></dd>
3320 <dt><span class="term"><span><strong class="command">dnssec-accept-expired</strong></span></span></dt>
3321 <dd><p>
3322 Accept expired signatures when verifying DNSSEC signatures.
3326 replay attacks.
3327 </p></dd>
3329 <dd><p>
3330 Specify whether query logging should be started when <span><strong class="command">named</strong></span>
3331 starts.
3333 then the query logging
3334 is determined by the presence of the logging category <span><strong class="command">queries</strong></span>.
3335 </p></dd>
3337 <dd>
3338 <p>
3339 This option is used to restrict the character set and syntax
3340 of
3341 certain domain names in master files and/or DNS responses
3342 received
3343 from the network. The default varies according to usage
3344 area. For
3345 <span><strong class="command">master</strong></span> zones the default is <span><strong class="command">fail</strong></span>.
3350 </p>
3351 <p>
3352 The rules for legal hostnames and mail domains are derived
3354 </p>
3356 applies to the owner names of A, AAAA and MX records.
3357 It also applies to the domain names in the RDATA of NS, SOA,
3358 MX, and SRV records.
3359 It also applies to the RDATA of PTR records where the owner
3360 name indicated that it is a reverse lookup of a hostname
3361 (the owner name ends in IN-ADDR.ARPA, IP6.ARPA, or IP6.INT).
3362 </p>
3363 </dd>
3364 <dt><span class="term"><span><strong class="command">check-dup-records</strong></span></span></dt>
3365 <dd><p>
3366 Check master zones for records that are treated as different
3367 by DNSSEC but are semantically equal in plain DNS. The
3371 </p></dd>
3373 <dd><p>
3374 Check whether the MX record appears to refer to a IP address.
3378 </p></dd>
3380 <dd><p>
3381 Check whether the MX record appears to refer to a IP address.
3385 </p></dd>
3386 <dt><span class="term"><span><strong class="command">check-wildcard</strong></span></span></dt>
3387 <dd><p>
3388 This option is used to check for non-terminal wildcards.
3389 The use of non-terminal wildcards is almost always as a
3390 result of a failure
3391 to understand the wildcard matching algorithm (RFC 1034).
3392 This option
3393 affects master zones. The default (<span><strong class="command">yes</strong></span>) is to check
3394 for non-terminal wildcards and issue a warning.
3395 </p></dd>
3396 <dt><span class="term"><span><strong class="command">check-integrity</strong></span></span></dt>
3397 <dd><p>
3398 Perform post load zone integrity checks on master
3399 zones. This checks that MX and SRV records refer
3400 to address (A or AAAA) records and that glue
3401 address records exist for delegated zones. For
3402 MX and SRV records only in-zone hostnames are
3403 checked (for out-of-zone hostnames use
3405 For NS records only names below top of zone are
3406 checked (for out-of-zone names and glue consistency
3409 </p></dd>
3410 <dt><span class="term"><span><strong class="command">check-mx-cname</strong></span></span></dt>
3411 <dd><p>
3413 fail, warn or ignore MX records that refer
3415 </p></dd>
3416 <dt><span class="term"><span><strong class="command">check-srv-cname</strong></span></span></dt>
3417 <dd><p>
3419 fail, warn or ignore SRV records that refer
3421 </p></dd>
3423 <dd><p>
3424 When performing integrity checks, also check that
3426 </p></dd>
3427 <dt><span class="term"><span><strong class="command">zero-no-soa-ttl</strong></span></span></dt>
3428 <dd><p>
3429 When returning authoritative negative responses to
3430 SOA queries set the TTL of the SOA record returned in
3431 the authority section to zero.
3433 </p></dd>
3434 <dt><span class="term"><span><strong class="command">zero-no-soa-ttl-cache</strong></span></span></dt>
3435 <dd><p>
3436 When caching a negative response to a SOA query
3437 set the TTL to zero.
3439 </p></dd>
3440 <dt><span class="term"><span><strong class="command">update-check-ksk</strong></span></span></dt>
3441 <dd>
3442 <p>
3444 check the KSK bit in each key to determine how the key
3445 should be used when generating RRSIGs for a secure zone.
3446 </p>
3447 <p>
3448 Ordinarily, zone-signing keys (that is, keys without the
3449 KSK bit set) are used to sign the entire zone, while
3450 key-signing keys (keys with the KSK bit set) are only
3451 used to sign the DNSKEY RRset at the zone apex.
3453 then the KSK bit is ignored; KSKs are treated as if they
3454 were ZSKs and are used to sign the entire zone. This is
3456 command line option.
3457 </p>
3458 <p>
3460 must be at least two active keys for every algorithm
3461 represented in the DNSKEY RRset: at least one KSK and one
3462 ZSK per algorithm. If there is any algorithm for which
3463 this requirement is not met, this option will be ignored
3464 for that algorithm.
3465 </p>
3466 </dd>
3467 <dt><span class="term"><span><strong class="command">dnssec-dnskey-kskonly</strong></span></span></dt>
3468 <dd>
3469 <p>
3472 keys (that is, keys with the KSK bit set) will be used
3473 to sign the DNSKEY RRset at the zone apex. Zone-signing
3474 keys (keys without the KSK bit set) will be used to sign
3475 the remainder of the zone, but not the DNSKEY RRset.
3476 This is similar to the
3478 </p>
3479 <p>
3483 </p>
3484 </dd>
3485 <dt><span class="term"><span><strong class="command">try-tcp-refresh</strong></span></span></dt>
3486 <dd><p>
3487 Try to refresh the zone using TCP if UDP queries fail.
3488 For BIND 8 compatibility, the default is
3490 </p></dd>
3491 <dt><span class="term"><span><strong class="command">dnssec-secure-to-insecure</strong></span></span></dt>
3492 <dd><p>
3493 Allow a zone to transition from secure to insecure by
3494 deleting all DNSKEY records. The default is
3496 </p></dd>
3497 </dl></div>
3498 </div>
3502 <p>
3503 The forwarding facility can be used to create a large site-wide
3504 cache on a few servers, reducing traffic over links to external
3505 name servers. It can also be used to allow queries by servers that
3506 do not have direct access to the Internet, but wish to look up
3507 exterior
3508 names anyway. Forwarding occurs only on those queries for which
3509 the server is not authoritative and does not have the answer in
3510 its cache.
3511 </p>
3514 <dd><p>
3515 This option is only meaningful if the
3517 the default, causes the server to query the forwarders
3518 first — and
3519 if that doesn't answer the question, the server will then
3520 look for
3522 specified, the
3523 server will only query the forwarders.
3524 </p></dd>
3526 <dd><p>
3527 Specifies the IP addresses to be used
3528 for forwarding. The default is the empty list (no
3529 forwarding).
3530 </p></dd>
3531 </dl></div>
3532 <p>
3533 Forwarding can also be configured on a per-domain basis, allowing
3534 for the global forwarding options to be overridden in a variety
3535 of ways. You can set particular domains to use different
3536 forwarders,
3539 Statement Grammar">the section called “<span><strong class="command">zone</strong></span>
3541 </p>
3542 </div>
3546 <p>
3547 Dual-stack servers are used as servers of last resort to work
3548 around
3549 problems in reachability due the lack of support for either IPv4
3550 or IPv6
3551 on the host machine.
3552 </p>
3554 <dt><span class="term"><span><strong class="command">dual-stack-servers</strong></span></span></dt>
3555 <dd><p>
3556 Specifies host names or addresses of machines with access to
3557 both IPv4 and IPv6 transports. If a hostname is used, the
3558 server must be able
3559 to resolve the name using only the transport it has. If the
3560 machine is dual
3561 stacked, then the <span><strong class="command">dual-stack-servers</strong></span> have no effect unless
3562 access to a transport has been disabled on the command line
3564 </p></dd>
3565 </dl></div>
3566 </div>
3570 <p>
3571 Access to the server can be restricted based on the IP address
3572 of the requesting system. See <a href="Bv9ARM.ch06.html#address_match_lists" title="Address Match Lists">the section called “Address Match Lists”</a> for
3573 details on how to specify IP address lists.
3574 </p>
3577 <dd><p>
3578 Specifies which hosts are allowed to
3579 notify this server, a slave, of zone changes in addition
3580 to the zone masters.
3582 specified in the
3584 it overrides the
3586 statement. It is only meaningful
3587 for a slave zone. If not specified, the default is to
3588 process notify messages
3589 only from a zone's master.
3590 </p></dd>
3592 <dd>
3593 <p>
3594 Specifies which hosts are allowed to ask ordinary
3597 statement, in which case it overrides the
3599 If not specified, the default is to allow queries
3600 from all hosts.
3601 </p>
3604 <p>
3606 used to specify access to the cache.
3607 </p>
3608 </div>
3609 </dd>
3610 <dt><span class="term"><span><strong class="command">allow-query-on</strong></span></span></dt>
3611 <dd>
3612 <p>
3613 Specifies which local addresses can accept ordinary
3614 DNS questions. This makes it possible, for instance,
3615 to allow queries on internal-facing interfaces but
3616 disallow them on external-facing ones, without
3617 necessarily knowing the internal network's addresses.
3618 </p>
3619 <p>
3622 statement, in which case it overrides the
3624 </p>
3625 <p>
3626 If not specified, the default is to allow queries
3627 on all addresses.
3628 </p>
3631 <p>
3633 used to specify access to the cache.
3634 </p>
3635 </div>
3636 </dd>
3637 <dt><span class="term"><span><strong class="command">allow-query-cache</strong></span></span></dt>
3638 <dd><p>
3639 Specifies which hosts are allowed to get answers
3647 </p></dd>
3648 <dt><span class="term"><span><strong class="command">allow-query-cache-on</strong></span></span></dt>
3649 <dd><p>
3650 Specifies which local addresses can give answers
3651 from the cache. If not specified, the default is
3652 to allow cache queries on any address,
3655 </p></dd>
3656 <dt><span class="term"><span><strong class="command">allow-recursion</strong></span></span></dt>
3657 <dd><p>
3658 Specifies which hosts are allowed to make recursive
3659 queries through this server. If
3663 is used if set, otherwise the default
3666 </p></dd>
3667 <dt><span class="term"><span><strong class="command">allow-recursion-on</strong></span></span></dt>
3668 <dd><p>
3669 Specifies which local addresses can accept recursive
3670 queries. If not specified, the default is to allow
3671 recursive queries on all addresses.
3672 </p></dd>
3674 <dd><p>
3675 Specifies which hosts are allowed to
3676 submit Dynamic DNS updates for master zones. The default is
3677 to deny
3678 updates from all hosts. Note that allowing updates based
3679 on the requestor's IP address is insecure; see
3680 <a href="Bv9ARM.ch07.html#dynamic_update_security" title="Dynamic Update Security">the section called “Dynamic Update Security”</a> for details.
3681 </p></dd>
3682 <dt><span class="term"><span><strong class="command">allow-update-forwarding</strong></span></span></dt>
3683 <dd>
3684 <p>
3685 Specifies which hosts are allowed to
3686 submit Dynamic DNS updates to slave zones to be forwarded to
3687 the
3689 which
3690 means that no update forwarding will be performed. To
3691 enable
3692 update forwarding, specify
3696 counterproductive, since
3697 the responsibility for update access control should rest
3698 with the
3699 master server, not the slaves.
3700 </p>
3701 <p>
3702 Note that enabling the update forwarding feature on a slave
3703 server
3704 may expose master servers relying on insecure IP address
3705 based
3706 access control to attacks; see <a href="Bv9ARM.ch07.html#dynamic_update_security" title="Dynamic Update Security">the section called “Dynamic Update Security”</a>
3707 for more details.
3708 </p>
3709 </dd>
3710 <dt><span class="term"><span><strong class="command">allow-v6-synthesis</strong></span></span></dt>
3711 <dd><p>
3712 This option was introduced for the smooth transition from
3713 AAAA
3714 to A6 and from "nibble labels" to binary labels.
3715 However, since both A6 and binary labels were then
3716 deprecated,
3717 this option was also deprecated.
3718 It is now ignored with some warning messages.
3719 </p></dd>
3720 <dt><span class="term"><span><strong class="command">allow-transfer</strong></span></span></dt>
3721 <dd><p>
3722 Specifies which hosts are allowed to
3723 receive zone transfers from the server. <span><strong class="command">allow-transfer</strong></span> may
3725 statement, in which
3726 case it overrides the <span><strong class="command">options allow-transfer</strong></span> statement.
3727 If not specified, the default is to allow transfers to all
3728 hosts.
3729 </p></dd>
3731 <dd><p>
3732 Specifies a list of addresses that the
3733 server will not accept queries from or use to resolve a
3734 query. Queries
3735 from these addresses will not be responded to. The default
3737 </p></dd>
3738 </dl></div>
3739 </div>
3743 <p>
3744 The interfaces and ports that the server will answer queries
3745 from may be specified using the <span><strong class="command">listen-on</strong></span> option. <span><strong class="command">listen-on</strong></span> takes
3747 The server will listen on all interfaces allowed by the address
3748 match list. If a port is not specified, port 53 will be used.
3749 </p>
3750 <p>
3752 allowed.
3753 For example,
3754 </p>
3757 </pre>
3758 <p>
3759 will enable the name server on port 53 for the IP address
3762 </p>
3763 <p>
3765 server will listen on port 53 on all IPv4 interfaces.
3766 </p>
3767 <p>
3769 specify the interfaces and the ports on which the server will
3770 listen
3771 for incoming queries sent using IPv6.
3772 </p>
3773 <p>
3774 When </p>
3776 <p> is
3777 specified
3780 the server does not bind a separate socket to each IPv6 interface
3781 address as it does for IPv4 if the operating system has enough API
3782 support for IPv6 (specifically if it conforms to RFC 3493 and RFC
3783 3542).
3784 Instead, it listens on the IPv6 wildcard address.
3785 If the system only has incomplete API support for IPv6, however,
3786 the behavior is the same as that for IPv4.
3787 </p>
3788 <p>
3789 A list of particular IPv6 addresses can also be specified, in
3790 which case
3791 the server listens on a separate socket for each specified
3792 address,
3793 regardless of whether the desired API is supported by the system.
3794 </p>
3795 <p>
3797 be used.
3798 For example,
3799 </p>
3802 </pre>
3803 <p>
3804 will enable the name server on port 53 for any IPv6 addresses
3805 (with a single wildcard socket),
3806 and on port 1234 of IPv6 addresses that is not in the prefix
3808 </p>
3809 <p>
3810 To make the server not listen on any IPv6 address, use
3811 </p>
3813 </pre>
3814 <p>
3816 specified, the server will not listen on any IPv6 address
3817 unless <span><strong class="command">-6</strong></span> is specified when <span><strong class="command">named</strong></span> is
3819 <span><strong class="command">named</strong></span> will listen on port 53 on all IPv6 interfaces by default.
3820 </p>
3821 </div>
3825 <p>
3826 If the server doesn't know the answer to a question, it will
3828 the address and port used for such queries. For queries sent over
3829 IPv6, there is a separate <span><strong class="command">query-source-v6</strong></span> option.
3830 If <span><strong class="command">address</strong></span> is <span><strong class="command">*</strong></span> (asterisk) or is omitted,
3832 will be used.
3833 </p>
3834 <p>
3835 If <span><strong class="command">port</strong></span> is <span><strong class="command">*</strong></span> or is omitted,
3836 a random port number from a pre-configured
3837 range is picked up and will be used for each query.
3838 The port range(s) is that specified in
3841 options, excluding the ranges specified in
3844 </p>
3845 <p>
3848 are:
3849 </p>
3851 query-source-v6 address * port *;
3852 </pre>
3853 <p>
3857 system provides a programming interface to retrieve the
3858 system's default range for ephemeral ports.
3859 If such an interface is available,
3861 default range; otherwise, it will use its own defaults:
3862 </p>
3864 use-v6-udp-ports { range 1024 65535; };
3865 </pre>
3866 <p>
3867 Note: make sure the ranges be sufficiently large for
3868 security. A desirable size depends on various parameters,
3869 but we generally recommend it contain at least 16384 ports
3870 (14 bits of entropy).
3871 Note also that the system's default range when used may be
3872 too small for this purpose, and that the range may even be
3875 is reloaded.
3876 It is encouraged to
3879 ranges are sufficiently large and are reasonably
3880 independent from the ranges used by other applications.
3881 </p>
3882 <p>
3883 Note: the operational configuration
3885 of some ports. For example, UNIX systems will not allow
3887 to use ports less than 1024.
3888 If such ports are included in the specified (or detected)
3889 set of query ports, the corresponding query attempts will
3890 fail, resulting in resolution failures or delay.
3891 It is therefore important to configure the set of ports
3892 that can be safely used in the expected operational environment.
3893 </p>
3894 <p>
3897 are:
3898 </p>
3900 avoid-v6-udp-ports {};
3901 </pre>
3902 <p>
3903 Note: BIND 9.5.0 introduced
3905 option to support a pool of such random ports, but this
3906 option is now obsolete because reusing the same ports in
3907 the pool may not be sufficiently secure.
3908 For the same reason, it is generally strongly discouraged to
3909 specify a particular port for the
3912 it implicitly disables the use of randomized port numbers.
3913 </p>
3915 <dt><span class="term"><span><strong class="command">use-queryport-pool</strong></span></span></dt>
3916 <dd><p>
3917 This option is obsolete.
3918 </p></dd>
3919 <dt><span class="term"><span><strong class="command">queryport-pool-ports</strong></span></span></dt>
3920 <dd><p>
3921 This option is obsolete.
3922 </p></dd>
3923 <dt><span class="term"><span><strong class="command">queryport-pool-updateinterval</strong></span></span></dt>
3924 <dd><p>
3925 This option is obsolete.
3926 </p></dd>
3927 </dl></div>
3930 <p>
3932 is used for both UDP and TCP queries, but the port applies only
3933 to UDP queries. TCP queries always use a random
3934 unprivileged port.
3935 </p>
3936 </div>
3939 <p>
3940 Solaris 2.5.1 and earlier does not support setting the source
3941 address for TCP sockets.
3942 </p>
3943 </div>
3946 <p>
3949 </p>
3950 </div>
3951 </div>
3955 <p>
3957 facilitate zone transfers
3958 and set limits on the amount of load that transfers place on the
3959 system. The following options apply to zone transfers.
3960 </p>
3963 <dd><p>
3964 Defines a global list of IP addresses of name servers
3965 that are also sent NOTIFY messages whenever a fresh copy of
3966 the
3967 zone is loaded, in addition to the servers listed in the
3968 zone's NS records.
3969 This helps to ensure that copies of the zones will
3970 quickly converge on stealth servers.
3971 Optionally, a port may be specified with each
3973 the notify messages to a port other than the
3974 default of 53.
3977 it will override
3980 statement
3983 not be sent NOTIFY messages for that zone. The default is
3984 the empty
3985 list (no global notification list).
3986 </p></dd>
3987 <dt><span class="term"><span><strong class="command">max-transfer-time-in</strong></span></span></dt>
3988 <dd><p>
3989 Inbound zone transfers running longer than
3990 this many minutes will be terminated. The default is 120
3991 minutes
3993 </p></dd>
3994 <dt><span class="term"><span><strong class="command">max-transfer-idle-in</strong></span></span></dt>
3995 <dd><p>
3996 Inbound zone transfers making no progress
3997 in this many minutes will be terminated. The default is 60
3998 minutes
4000 </p></dd>
4001 <dt><span class="term"><span><strong class="command">max-transfer-time-out</strong></span></span></dt>
4002 <dd><p>
4003 Outbound zone transfers running longer than
4004 this many minutes will be terminated. The default is 120
4005 minutes
4007 </p></dd>
4008 <dt><span class="term"><span><strong class="command">max-transfer-idle-out</strong></span></span></dt>
4009 <dd><p>
4010 Outbound zone transfers making no progress
4011 in this many minutes will be terminated. The default is 60
4012 minutes (1
4014 </p></dd>
4015 <dt><span class="term"><span><strong class="command">serial-query-rate</strong></span></span></dt>
4016 <dd><p>
4017 Slave servers will periodically query master servers
4018 to find out if zone serial numbers have changed. Each such
4019 query uses
4020 a minute amount of the slave server's network bandwidth. To
4021 limit the
4022 amount of bandwidth used, BIND 9 limits the rate at which
4023 queries are
4025 an integer, is the maximum number of queries sent per
4026 second.
4027 The default is 20.
4028 </p></dd>
4029 <dt><span class="term"><span><strong class="command">serial-queries</strong></span></span></dt>
4030 <dd><p>
4032 option
4033 set the maximum number of concurrent serial number queries
4034 allowed to be outstanding at any given time.
4035 BIND 9 does not limit the number of outstanding
4036 serial queries and ignores the <span><strong class="command">serial-queries</strong></span> option.
4037 Instead, it limits the rate at which the queries are sent
4039 </p></dd>
4040 <dt><span class="term"><span><strong class="command">transfer-format</strong></span></span></dt>
4041 <dd><p>
4042 Zone transfers can be sent using two different formats,
4046 on the master server to determine which format it sends.
4048 resource record transferred.
4050 records as possible into a message.
4052 only supported by relatively new slave servers,
4056 recent Microsoft Windows nameservers.
4060 statement.
4061 </p></dd>
4063 <dd><p>
4064 The maximum number of inbound zone transfers
4067 speed up the convergence
4068 of slave zones, but it also may increase the load on the
4069 local system.
4070 </p></dd>
4072 <dd><p>
4073 The maximum number of outbound zone transfers
4074 that can be running concurrently. Zone transfer requests in
4075 excess
4077 </p></dd>
4078 <dt><span class="term"><span><strong class="command">transfers-per-ns</strong></span></span></dt>
4079 <dd><p>
4080 The maximum number of inbound zone transfers
4081 that can be concurrently transferring from a given remote
4082 name server.
4085 may
4086 speed up the convergence of slave zones, but it also may
4087 increase
4088 the load on the remote name server. <span><strong class="command">transfers-per-ns</strong></span> may
4089 be overridden on a per-server basis by using the <span><strong class="command">transfers</strong></span> phrase
4091 </p></dd>
4092 <dt><span class="term"><span><strong class="command">transfer-source</strong></span></span></dt>
4093 <dd>
4095 determines which local address will be bound to IPv4
4096 TCP connections used to fetch zones transferred
4097 inbound by the server. It also determines the
4098 source IPv4 address, and optionally the UDP port,
4099 used for the refresh queries and forwarded dynamic
4100 updates. If not set, it defaults to a system
4101 controlled value which will usually be the address
4102 of the interface "closest to" the remote end. This
4103 address must appear in the remote end's
4105 zone being transferred, if one is specified. This
4106 statement sets the
4108 but can be overridden on a per-view or per-zone
4109 basis by including a
4113 file.
4114 </p>
4117 <p>
4118 Solaris 2.5.1 and earlier does not support setting the
4119 source address for TCP sockets.
4120 </p>
4121 </div>
4122 </dd>
4123 <dt><span class="term"><span><strong class="command">transfer-source-v6</strong></span></span></dt>
4124 <dd><p>
4126 except zone transfers are performed using IPv6.
4127 </p></dd>
4128 <dt><span class="term"><span><strong class="command">alt-transfer-source</strong></span></span></dt>
4129 <dd>
4130 <p>
4131 An alternate transfer source if the one listed in
4134 set.
4135 </p>
4138 If you do not wish the alternate transfer source
4139 to be used, you should set
4141 appropriately and you should not depend upon
4142 getting an answer back to the first refresh
4143 query.
4144 </div>
4145 </dd>
4146 <dt><span class="term"><span><strong class="command">alt-transfer-source-v6</strong></span></span></dt>
4147 <dd><p>
4148 An alternate transfer source if the one listed in
4151 set.
4152 </p></dd>
4153 <dt><span class="term"><span><strong class="command">use-alt-transfer-source</strong></span></span></dt>
4154 <dd><p>
4155 Use the alternate transfer sources or not. If views are
4157 otherwise it defaults to
4159 compatibility).
4160 </p></dd>
4162 <dd>
4164 determines which local source address, and
4165 optionally UDP port, will be used to send NOTIFY
4166 messages. This address must appear in the slave
4170 for all zones, but can be overridden on a per-zone or
4171 per-view basis by including a
4175 file.
4176 </p>
4179 <p>
4180 Solaris 2.5.1 and earlier does not support setting the
4181 source address for TCP sockets.
4182 </p>
4183 </div>
4184 </dd>
4185 <dt><span class="term"><span><strong class="command">notify-source-v6</strong></span></span></dt>
4186 <dd><p>
4188 but applies to notify messages sent to IPv6 addresses.
4189 </p></dd>
4190 </dl></div>
4191 </div>
4195 <p>
4200 specify a list of IPv4 and IPv6 UDP ports that will be
4201 used or not used as source ports for UDP messages.
4202 See <a href="Bv9ARM.ch06.html#query_address" title="Query Address">the section called “Query Address”</a> about how the
4203 available ports are determined.
4204 For example, with the following configuration
4205 </p>
4207 use-v6-udp-ports { range 32768 65535; };
4209 </pre>
4210 <p>
4211 UDP ports of IPv6 messages sent
4215 </p>
4216 <p>
4219 to prevent <span><strong class="command">named</strong></span> from choosing as its random source port a
4220 port that is blocked by your firewall or a port that is
4221 used by other applications;
4222 if a query went out with a source port blocked by a
4223 firewall, the
4224 answer would not get by the firewall and the name server would
4225 have to query again.
4226 Note: the desired range can also be represented only with
4230 sense; they are provided for backward compatibility and
4231 to possibly simplify the port specification.
4232 </p>
4233 </div>
4237 <p>
4238 The server's usage of many system resources can be limited.
4239 Scaled values are allowed when specifying resource limits. For
4242 one
4244 unlimited use, or the
4246 uses the limit
4247 that was in force when the server was started. See the description
4248 of <span><strong class="command">size_spec</strong></span> in <a href="Bv9ARM.ch06.html#configuration_file_elements" title="Configuration File Elements">the section called “Configuration File Elements”</a>.
4249 </p>
4250 <p>
4251 The following options set operating system resource limits for
4252 the name server process. Some operating systems don't support
4253 some or
4254 any of the limits. On such systems, a warning will be issued if
4255 the
4256 unsupported limit is used.
4257 </p>
4260 <dd><p>
4261 The maximum size of a core dump. The default
4263 </p></dd>
4265 <dd><p>
4266 The maximum amount of data memory the server
4268 This is a hard limit on server memory usage.
4269 If the server attempts to allocate memory in excess of this
4270 limit, the allocation will fail, which may in turn leave
4271 the server unable to perform DNS service. Therefore,
4272 this option is rarely useful as a way of limiting the
4273 amount of memory used by the server, but it can be used
4274 to raise an operating system data size limit that is
4275 too small by default. If you wish to limit the amount
4276 of memory used by the server, use the
4279 options instead.
4280 </p></dd>
4282 <dd><p>
4283 The maximum number of files the server
4285 </p></dd>
4287 <dd><p>
4288 The maximum amount of stack memory the server
4290 </p></dd>
4291 </dl></div>
4292 </div>
4296 <p>
4297 The following options set limits on the server's
4298 resource consumption that are enforced internally by the
4299 server rather than the operating system.
4300 </p>
4302 <dt><span class="term"><span><strong class="command">max-ixfr-log-size</strong></span></span></dt>
4303 <dd><p>
4304 This option is obsolete; it is accepted
4305 and ignored for BIND 8 compatibility. The option
4307 similar function in BIND 9.
4308 </p></dd>
4309 <dt><span class="term"><span><strong class="command">max-journal-size</strong></span></span></dt>
4310 <dd><p>
4311 Sets a maximum size for each journal file
4312 (see <a href="Bv9ARM.ch04.html#journal" title="The journal file">the section called “The journal file”</a>). When the journal file
4313 approaches
4314 the specified size, some of the oldest transactions in the
4315 journal
4316 will be automatically removed. The default is
4318 This may also be set on a per-zone basis.
4319 </p></dd>
4320 <dt><span class="term"><span><strong class="command">host-statistics-max</strong></span></span></dt>
4321 <dd><p>
4322 In BIND 8, specifies the maximum number of host statistics
4323 entries to be kept.
4324 Not implemented in BIND 9.
4325 </p></dd>
4326 <dt><span class="term"><span><strong class="command">recursive-clients</strong></span></span></dt>
4327 <dd><p>
4328 The maximum number of simultaneous recursive lookups
4329 the server will perform on behalf of clients. The default
4330 is
4332 client uses a fair
4333 bit of memory, on the order of 20 kilobytes, the value of
4334 the
4336 have to be decreased
4337 on hosts with limited memory.
4338 </p></dd>
4340 <dd><p>
4341 The maximum number of simultaneous client TCP
4342 connections that the server will accept.
4344 </p></dd>
4345 <dt><span class="term"><span><strong class="command">reserved-sockets</strong></span></span></dt>
4346 <dd>
4347 <p>
4348 The number of file descriptors reserved for TCP, stdio,
4349 etc. This needs to be big enough to cover the number of
4350 interfaces <span><strong class="command">named</strong></span> listens on, <span><strong class="command">tcp-clients</strong></span> as well as
4351 to provide room for outgoing TCP queries and incoming zone
4355 maxsockets (-S). This option may be removed in the future.
4356 </p>
4357 <p>
4358 This option has little effect on Windows.
4359 </p>
4360 </dd>
4361 <dt><span class="term"><span><strong class="command">max-cache-size</strong></span></span></dt>
4362 <dd><p>
4363 The maximum amount of memory to use for the
4364 server's cache, in bytes.
4365 When the amount of data in the cache
4366 reaches this limit, the server will cause records to expire
4367 prematurely based on an LRU based strategy so that
4368 the limit is not exceeded.
4369 A value of 0 is special, meaning that
4370 records are purged from the cache only when their
4371 TTLs expire.
4373 means the maximum value of 32-bit unsigned integers
4374 (0xffffffff), which may not have the same effect as
4376 memory space.
4377 Any positive values less than 2MB will be ignored reset
4378 to 2MB.
4379 In a server with multiple views, the limit applies
4380 separately to the cache of each view.
4381 The default is 0.
4382 </p></dd>
4383 <dt><span class="term"><span><strong class="command">tcp-listen-queue</strong></span></span></dt>
4384 <dd><p>
4385 The listen queue depth. The default and minimum is 3.
4386 If the kernel supports the accept filter "dataready" this
4387 also controls how
4388 many TCP connections that will be queued in kernel space
4389 waiting for
4390 some data before being passed to accept. Values less than 3
4391 will be
4392 silently raised.
4393 </p></dd>
4394 </dl></div>
4395 </div>
4400 <dt><span class="term"><span><strong class="command">cleaning-interval</strong></span></span></dt>
4401 <dd><p>
4402 This interval is effectively obsolete. Previously,
4403 the server would remove expired resource records
4406 memory in a more sophisticated manner and does not
4407 rely on the periodic cleaning any more.
4408 Specifying this option therefore has no effect on
4409 the server's behavior.
4410 </p></dd>
4411 <dt><span class="term"><span><strong class="command">heartbeat-interval</strong></span></span></dt>
4412 <dd><p>
4413 The server will perform zone maintenance tasks
4415 interval expires. The default is 60 minutes. Reasonable
4416 values are up
4418 (40320 minutes).
4419 If set to 0, no zone maintenance for these zones will occur.
4420 </p></dd>
4421 <dt><span class="term"><span><strong class="command">interface-interval</strong></span></span></dt>
4422 <dd><p>
4423 The server will scan the network interface list
4425 minutes. The default
4427 If set to 0, interface scanning will only occur when
4428 the configuration file is loaded. After the scan, the
4429 server will
4430 begin listening for queries on any newly discovered
4431 interfaces (provided they are allowed by the
4433 will
4434 stop listening on interfaces that have gone away.
4435 </p></dd>
4436 <dt><span class="term"><span><strong class="command">statistics-interval</strong></span></span></dt>
4437 <dd>
4438 <p>
4439 Name server statistics will be logged
4441 minutes. The default is
4443 If set to 0, no statistics will be logged.
4444 </p>
4447 <p>
4448 Not yet implemented in
4450 </p>
4451 </div>
4452 </dd>
4453 </dl></div>
4454 </div>
4458 <p>
4459 All other things being equal, when the server chooses a name
4460 server
4461 to query from a list of name servers, it prefers the one that is
4462 topologically closest to itself. The <span><strong class="command">topology</strong></span> statement
4464 interprets it
4465 in a special way. Each top-level list element is assigned a
4466 distance.
4467 Non-negated elements get a distance based on their position in the
4468 list, where the closer the match is to the start of the list, the
4469 shorter the distance is between it and the server. A negated match
4470 will be assigned the maximum distance from the server. If there
4471 is no match, the address will get a distance which is further than
4472 any non-negated list element, and closer than any negated element.
4473 For example,
4474 </p>
4479 };</pre>
4480 <p>
4481 will prefer servers on network 10 the most, followed by hosts
4484 is preferred least of all.
4485 </p>
4486 <p>
4487 The default topology is
4488 </p>
4490 </pre>
4493 <p>
4496 </p>
4497 </div>
4498 </div>
4501 <a name="the_sortlist_statement"></a>The <span><strong class="command">sortlist</strong></span> Statement</h4></div></div></div>
4502 <p>
4503 The response to a DNS query may consist of multiple resource
4504 records (RRs) forming a resource records set (RRset).
4505 The name server will normally return the
4506 RRs within the RRset in an indeterminate order
4508 statement in <a href="Bv9ARM.ch06.html#rrset_ordering" title="RRset Ordering">the section called “RRset Ordering”</a>).
4509 The client resolver code should rearrange the RRs as appropriate,
4510 that is, using any addresses on the local net in preference to
4511 other addresses.
4512 However, not all resolvers can do this or are correctly
4513 configured.
4514 When a client is using a local server, the sorting can be performed
4515 in the server, based on the client's address. This only requires
4516 configuring the name servers, not all the clients.
4517 </p>
4518 <p>
4520 takes
4522 interprets it even
4524 statement
4525 does (<a href="Bv9ARM.ch06.html#topology" title="Topology">the section called “Topology”</a>).
4528 one or two elements. The first element (which may be an IP
4529 address,
4530 an IP prefix, an ACL name or a nested <span><strong class="command">address_match_list</strong></span>)
4531 of each top level list is checked against the source address of
4532 the query until a match is found.
4533 </p>
4534 <p>
4535 Once the source address of the query has been matched, if
4536 the top level statement contains only one element, the actual
4537 primitive
4538 element that matched the source address is used to select the
4539 address
4540 in the response to move to the beginning of the response. If the
4541 statement is a list of two elements, then the second element is
4544 level element
4545 is assigned a distance and the address in the response with the
4546 minimum
4547 distance is moved to the beginning of the response.
4548 </p>
4549 <p>
4550 In the following example, any queries received from any of
4551 the addresses of the host itself will get responses preferring
4552 addresses
4553 on any of the locally connected networks. Next most preferred are
4554 addresses
4557 or
4561 and
4565 their directly connected networks.
4566 </p>
4568 // IF the local host
4569 // THEN first fit on the following nets
4570 { localhost;
4571 { localnets;
4588 };
4589 };</pre>
4590 <p>
4591 The following example will give reasonable behavior for the
4592 local host and hosts on directly connected networks. It is similar
4593 to the behavior of the address sort in <acronym class="acronym">BIND</acronym> 4.9.x. Responses sent
4594 to queries from the local host will favor any of the directly
4595 connected
4596 networks. Responses sent to queries from any other hosts on a
4597 directly
4598 connected network will prefer addresses on that same network.
4599 Responses
4600 to other queries will not be sorted.
4601 </p>
4603 { localhost; localnets; };
4604 { localnets; };
4605 };
4606 </pre>
4607 </div>
4611 <p>
4612 When multiple records are returned in an answer it may be
4613 useful to configure the order of the records placed into the
4614 response.
4616 configuration
4617 of the ordering of the records in a multiple record response.
4619 <a href="Bv9ARM.ch06.html#the_sortlist_statement" title="The sortlist Statement">the section called “The <span><strong class="command">sortlist</strong></span> Statement”</a>.
4620 </p>
4621 <p>
4623 follows:
4624 </p>
4625 <p>
4630 </p>
4631 <p>
4634 If no name is specified, the default is "<span><strong class="command">*</strong></span>" (asterisk).
4635 </p>
4636 <p>
4638 </p>
4640 <colgroup>
4641 <col>
4642 <col>
4643 </colgroup>
4644 <tbody>
4645 <tr>
4646 <td>
4648 </td>
4649 <td>
4650 <p>
4651 Records are returned in the order they
4652 are defined in the zone file.
4653 </p>
4654 </td>
4655 </tr>
4656 <tr>
4657 <td>
4659 </td>
4660 <td>
4661 <p>
4662 Records are returned in some random order.
4663 </p>
4664 </td>
4665 </tr>
4666 <tr>
4667 <td>
4669 </td>
4670 <td>
4671 <p>
4672 Records are returned in a cyclic round-robin order.
4673 </p>
4674 <p>
4676 "--enable-fixed-rrset" option at compile time, then
4677 the initial ordering of the RRset will match the
4678 one specified in the zone file.
4679 </p>
4680 </td>
4681 </tr>
4682 </tbody>
4683 </table></div>
4684 <p>
4685 For example:
4686 </p>
4688 class IN type A name "host.example.com" order random;
4689 order cyclic;
4690 };
4691 </pre>
4692 <p>
4693 will cause any responses for type A records in class IN that
4695 suffix, to always be returned
4696 in random order. All other records are returned in cyclic order.
4697 </p>
4698 <p>
4700 appear,
4701 they are not combined — the last one applies.
4702 </p>
4705 <p>
4708 "fixed" ordering by default. Fixed ordering can be enabled
4709 at compile time by specifying "--enable-fixed-rrset" on
4710 the "configure" command line.
4711 </p>
4712 </div>
4713 </div>
4719 <dd><p>
4720 Sets the number of seconds to cache a
4721 lame server indication. 0 disables caching. (This is
4724 maximum value is
4726 </p></dd>
4727 <dt><span class="term"><span><strong class="command">max-ncache-ttl</strong></span></span></dt>
4728 <dd><p>
4729 To reduce network traffic and increase performance,
4730 the server stores negative answers. <span><strong class="command">max-ncache-ttl</strong></span> is
4731 used to set a maximum retention time for these answers in
4732 the server
4733 in seconds. The default
4734 <span><strong class="command">max-ncache-ttl</strong></span> is <code class="literal">10800</code> seconds (3 hours).
4736 7 days and will
4737 be silently truncated to 7 days if set to a greater value.
4738 </p></dd>
4740 <dd><p>
4741 Sets the maximum time for which the server will
4742 cache ordinary (positive) answers. The default is
4743 one week (7 days).
4744 A value of zero may cause all queries to return
4745 SERVFAIL, because of lost caches of intermediate
4746 RRsets (such as NS and glue AAAA/A records) in the
4747 resolution process.
4748 </p></dd>
4750 <dd>
4751 <p>
4752 The minimum number of root servers that
4753 is required for a request for the root servers to be
4754 accepted. The default
4756 </p>
4759 <p>
4761 </p>
4762 </div>
4763 </dd>
4764 <dt><span class="term"><span><strong class="command">sig-validity-interval</strong></span></span></dt>
4765 <dd>
4766 <p>
4767 Specifies the number of days into the future when
4768 DNSSEC signatures automatically generated as a
4769 result of dynamic updates (<a href="Bv9ARM.ch04.html#dynamic_update" title="Dynamic Update">the section called “Dynamic Update”</a>) will expire. There
4770 is an optional second field which specifies how
4771 long before expiry that the signatures will be
4772 regenerated. If not specified, the signatures will
4774 field is specified in days if the base interval is
4775 greater than 7 days otherwise it is specified in hours.
4779 </p>
4780 <p>
4781 The signature inception time is unconditionally
4782 set to one hour before the current time to allow
4783 for a limited amount of clock skew.
4784 </p>
4785 <p>
4787 should be, at least, several multiples of the SOA
4788 expire interval to allow for reasonable interaction
4789 between the various timer and expiry dates.
4790 </p>
4791 </dd>
4792 <dt><span class="term"><span><strong class="command">sig-signing-nodes</strong></span></span></dt>
4793 <dd><p>
4794 Specify the maximum number of nodes to be
4795 examined in each quantum when signing a zone with
4796 a new DNSKEY. The default is
4798 </p></dd>
4799 <dt><span class="term"><span><strong class="command">sig-signing-signatures</strong></span></span></dt>
4800 <dd><p>
4801 Specify a threshold number of signatures that
4802 will terminate processing a quantum when signing
4803 a zone with a new DNSKEY. The default is
4805 </p></dd>
4806 <dt><span class="term"><span><strong class="command">sig-signing-type</strong></span></span></dt>
4807 <dd>
4808 <p>
4809 Specify a private RDATA type to be used when generating
4810 key signing records. The default is
4812 </p>
4813 <p>
4814 It is expected that this parameter may be removed
4815 in a future version once there is a standard type.
4816 </p>
4817 </dd>
4818 <dt>
4819 <span class="term"><span><strong class="command">min-refresh-time</strong></span>, </span><span class="term"><span><strong class="command">max-refresh-time</strong></span>, </span><span class="term"><span><strong class="command">min-retry-time</strong></span>, </span><span class="term"><span><strong class="command">max-retry-time</strong></span></span>
4820 </dt>
4821 <dd>
4822 <p>
4823 These options control the server's behavior on refreshing a
4824 zone
4825 (querying for SOA changes) or retrying failed transfers.
4826 Usually the SOA values for the zone are used, but these
4827 values
4828 are set by the master, giving slave server administrators
4829 little
4830 control over their contents.
4831 </p>
4832 <p>
4833 These options allow the administrator to set a minimum and
4834 maximum
4835 refresh and retry time either per-zone, per-view, or
4836 globally.
4837 These options are valid for slave and stub zones,
4838 and clamp the SOA refresh and retry times to the specified
4839 values.
4840 </p>
4841 </dd>
4843 <dd>
4844 <p>
4845 Sets the advertised EDNS UDP buffer size in bytes
4846 to control the size of packets received.
4848 will be silently adjusted). The default value
4849 is 4096. The usual reason for setting
4851 value is to get UDP answers to pass through broken
4852 firewalls that block fragmented packets and/or
4853 block UDP packets that are greater than 512 bytes.
4854 </p>
4855 <p>
4857 if it get a series of timeout at the initial value. 512
4858 bytes is not being offered to encourage sites to fix their
4859 firewalls. Small EDNS UDP sizes will result in the
4860 excessive use of TCP.
4861 </p>
4862 </dd>
4864 <dd>
4865 <p>
4866 Sets the maximum EDNS UDP message size
4869 range will be silently adjusted). The default
4870 value is 4096. The usual reason for setting
4872 value is to get UDP answers to pass through broken
4873 firewalls that block fragmented packets and/or
4874 block UDP packets that are greater than 512 bytes.
4875 This is independent of the advertised receive
4877 </p>
4878 <p>
4879 Setting this to a low value will encourge additional
4880 TCP traffic to the nameserver.
4881 </p>
4882 </dd>
4883 <dt><span class="term"><span><strong class="command">masterfile-format</strong></span></span></dt>
4884 <dd><p>Specifies
4885 the file format of zone files (see
4886 <a href="Bv9ARM.ch06.html#zonefile_format" title="Additional File Formats">the section called “Additional File Formats”</a>).
4888 standard textual representation. Files in other formats
4891 Note that when a zone file in a different format than
4892 <code class="constant">text</code> is loaded, <span><strong class="command">named</strong></span>
4893 may omit some of the checks which would be performed for a
4898 must be generated with the same check level as that
4900 file. This statement sets the
4902 but can be overridden on a per-zone or per-view basis
4906 file.
4907 </p></dd>
4908 <dt>
4909 <a name="clients-per-query"></a><span class="term"><span><strong class="command">clients-per-query</strong></span>, </span><span class="term"><span><strong class="command">max-clients-per-query</strong></span></span>
4910 </dt>
4911 <dd>
4912 <p>These set the
4913 initial value (minimum) and maximum number of recursive
4914 simultaneous clients for any given query
4916 before dropping additional clients. <span><strong class="command">named</strong></span> will attempt to
4917 self tune this value and changes will be logged. The
4919 </p>
4920 <p>
4921 This value should reflect how many queries come in for
4922 a given name in the time it takes to resolve that name.
4923 If the number of queries exceed this value, <span><strong class="command">named</strong></span> will
4924 assume that it is dealing with a non-responsive zone
4925 and will drop additional queries. If it gets a response
4926 after dropping queries, it will raise the estimate. The
4927 estimate will then be lowered in 20 minutes if it has
4928 remained unchanged.
4929 </p>
4930 <p>
4932 then there is no limit on the number of clients per query
4933 and no queries will be dropped.
4934 </p>
4935 <p>
4937 then there is no upper bound other than imposed by
4939 </p>
4940 </dd>
4942 <dd><p>
4943 The delay, in seconds, between sending sets of notify
4944 messages for a zone. The default is zero.
4945 </p></dd>
4946 </dl></div>
4947 </div>
4951 <p>
4952 The server provides some helpful diagnostic information
4953 through a number of built-in zones under the
4956 of a
4957 built-in view (see <a href="Bv9ARM.ch06.html#view_statement_grammar" title="view Statement Grammar">the section called “<span><strong class="command">view</strong></span> Statement Grammar”</a>) of
4958 class
4960 default view of
4962 server options
4964 the these zones.
4965 If you feel the need to disable these zones, use the options
4967 view by
4969 that matches all clients.
4970 </p>
4973 <dd><p>
4974 The version the server should report
4976 with type <span><strong class="command">TXT</strong></span>, class <span><strong class="command">CHAOS</strong></span>.
4977 The default is the real version number of this server.
4979 disables processing of the queries.
4980 </p></dd>
4982 <dd><p>
4983 The hostname the server should report via a query of
4985 with type <span><strong class="command">TXT</strong></span>, class <span><strong class="command">CHAOS</strong></span>.
4986 This defaults to the hostname of the machine hosting the
4987 name server as
4988 found by the gethostname() function. The primary purpose of such queries
4989 is to
4990 identify which of a group of anycast servers is actually
4991 answering your queries. Specifying <span><strong class="command">hostname none;</strong></span>
4992 disables processing of the queries.
4993 </p></dd>
4995 <dd><p>
4996 The ID the server should report when receiving a Name
4997 Server Identifier (NSID) query, or a query of the name
4999 <span><strong class="command">TXT</strong></span>, class <span><strong class="command">CHAOS</strong></span>.
5000 The primary purpose of such queries is to
5001 identify which of a group of anycast servers is actually
5002 answering your queries. Specifying <span><strong class="command">server-id none;</strong></span>
5003 disables processing of the queries.
5004 Specifying <span><strong class="command">server-id hostname;</strong></span> will cause <span><strong class="command">named</strong></span> to
5005 use the hostname as found by the gethostname() function.
5006 The default <span><strong class="command">server-id</strong></span> is <span><strong class="command">none</strong></span>.
5007 </p></dd>
5008 </dl></div>
5009 </div>
5013 <p>
5014 Named has some built-in empty zones (SOA and NS records only).
5015 These are for zones that should normally be answered locally
5016 and which queries should not be sent to the Internet's root
5017 servers. The official servers which cover these namespaces
5018 return NXDOMAIN responses to these queries. In particular,
5019 these cover the reverse namespace for addresses from RFC 1918 and
5020 RFC 3330. They also include the reverse namespace for IPv6 local
5021 address (locally assigned), IPv6 link local addresses, the IPv6
5022 loopback address and the IPv6 unknown address.
5023 </p>
5024 <p>
5025 Named will attempt to determine if a built-in zone already exists
5026 or is active (covered by a forward-only forwarding declaration)
5027 and will not create an empty zone in that case.
5028 </p>
5029 <p>
5030 The current list of empty zones is:
5031 </p>
5045 </ul></div>
5046 <p>
5047 </p>
5048 <p>
5049 Empty zones are settable at the view level and only apply to
5050 views of class IN. Disabled empty zones are only inherited
5051 from options if there are no disabled empty zones specified
5052 at the view level. To override the options list of disabled
5053 zones, you can disable the root zone at the view level, for example:
5054 </p>
5056 disable-empty-zone ".";
5057 </pre>
5058 <p>
5059 </p>
5060 <p>
5061 If you are using the address ranges covered here, you should
5062 already have reverse zones covering the addresses you use.
5063 In practice this appears to not be the case with many queries
5064 being made to the infrastructure servers for names in these
5065 spaces. So many in fact that sacrificial servers were needed
5066 to be deployed to channel the query load away from the
5067 infrastructure servers.
5068 </p>
5071 The real parent servers for these zones should disable all
5072 empty zone under the parent zone they serve. For the real
5073 root servers, this is all built-in empty zones. This will
5074 enable them to return referrals to deeper in the tree.
5075 </div>
5078 <dd><p>
5079 Specify what server name will appear in the returned
5080 SOA record for empty zones. If none is specified, then
5081 the zone's name will be used.
5082 </p></dd>
5084 <dd><p>
5085 Specify what contact name will appear in the returned
5086 SOA record for empty zones. If none is specified, then
5087 "." will be used.
5088 </p></dd>
5089 <dt><span class="term"><span><strong class="command">empty-zones-enable</strong></span></span></dt>
5090 <dd><p>
5091 Enable or disable all empty zones. By default, they
5092 are enabled.
5093 </p></dd>
5094 <dt><span class="term"><span><strong class="command">disable-empty-zone</strong></span></span></dt>
5095 <dd><p>
5096 Disable individual empty zones. By default, none are
5097 disabled. This option can be specified multiple times.
5098 </p></dd>
5099 </dl></div>
5100 </div>
5104 <p>
5105 The additional section cache, also called <span><strong class="command">acache</strong></span>,
5106 is an internal cache to improve the response performance of BIND 9.
5107 When additional section caching is enabled, BIND 9 will
5108 cache an internal short-cut to the additional section content for
5109 each answer RR.
5111 mechanism of BIND 9, and is not related to the DNS caching
5112 server function.
5113 </p>
5114 <p>
5115 Additional section caching does not change the
5116 response content (except the RRsets ordering of the additional
5117 section, see below), but can improve the response performance
5118 significantly.
5119 It is particularly effective when BIND 9 acts as an authoritative
5120 server for a zone that has many delegations with many glue RRs.
5121 </p>
5122 <p>
5123 In order to obtain the maximum performance improvement
5124 from additional section caching, setting
5128 does not short-cut of additional section information from the
5129 DNS cache data.
5130 </p>
5131 <p>
5133 that it requires much more
5134 memory for the internal cached data.
5135 Thus, if the response performance does not matter and memory
5136 consumption is much more critical, the
5140 It is also possible to specify the upper limit of memory
5141 consumption
5143 </p>
5144 <p>
5145 Additional section caching also has a minor effect on the
5146 RRset ordering in the additional section.
5149 section as well as the answer and authority sections.
5150 However, additional section caching fixes the ordering when it
5151 first caches an RRset for the additional section, and the same
5152 ordering will be kept in succeeding responses, regardless of the
5154 The effect of this should be minor, however, since an
5155 RRset in the additional section
5156 typically only contains a small number of RRs (and in many cases
5157 it only contains a single RR), in which case the
5158 ordering does not matter much.
5159 </p>
5160 <p>
5161 The following is a summary of options related to
5163 </p>
5166 <dd><p>
5169 </p></dd>
5170 <dt><span class="term"><span><strong class="command">acache-cleaning-interval</strong></span></span></dt>
5171 <dd><p>
5172 The server will remove stale cache entries, based on an LRU
5173 based
5174 algorithm, every <span><strong class="command">acache-cleaning-interval</strong></span> minutes.
5175 The default is 60 minutes.
5176 If set to 0, no periodic cleaning will occur.
5177 </p></dd>
5178 <dt><span class="term"><span><strong class="command">max-acache-size</strong></span></span></dt>
5179 <dd><p>
5180 The maximum amount of memory in bytes to use for the server's acache.
5181 When the amount of data in the acache reaches this limit,
5182 the server
5183 will clean more aggressively so that the limit is not
5184 exceeded.
5185 In a server with multiple views, the limit applies
5186 separately to the
5187 acache of each view.
5189 </p></dd>
5190 </dl></div>
5191 </div>
5195 <p>
5197 out DNS responses from external DNS servers containing
5198 certain types of data in the answer section.
5199 Specifically, it can reject address (A or AAAA) records if
5200 the corresponding IPv4 or IPv6 addresses match the given
5203 It can also reject CNAME or DNAME records if the "alias"
5204 name (i.e., the CNAME alias or the substituted query name
5205 due to DNAME) matches the
5208 "match" means the alias name is a subdomain of one of
5212 matches the list will be accepted regardless of the filter
5213 setting.
5214 Likewise, if the alias name is a subdomain of the
5216 filter will not apply;
5217 for example, even if "example.com" is specified for
5219 </p>
5221 <p>
5222 returned by an "example.com" server will be accepted.
5223 </p>
5224 <p>
5229 are meaningful;
5231 </p>
5232 <p>
5233 If a response message is rejected due to the filtering,
5234 the entire message is discarded without being cached, and
5235 a SERVFAIL error will be returned to the client.
5236 </p>
5237 <p>
5238 This filtering is intended to prevent "DNS rebinding attacks," in
5239 which an attacker, in response to a query for a domain name the
5240 attacker controls, returns an IP address within your own network or
5241 an alias name within your own domain.
5242 A naive web browser or script could then serve as an
5243 unintended proxy, allowing the attacker
5244 to get access to an internal node of your local network
5245 that couldn't be externally accessed otherwise.
5246 See the paper available at
5248 http://portal.acm.org/citation.cfm?id=1315245.1315298
5249 </a>
5250 for more details about the attacks.
5251 </p>
5252 <p>
5253 For example, if you own a domain named "example.net" and
5255 you might specify the following rules:
5256 </p>
5257 <pre class="programlisting">deny-answer-addresses { 192.0.2.0/24; } except-from { "example.net"; };
5258 deny-answer-aliases { "example.net"; };
5259 </pre>
5260 <p>
5261 If an external attacker lets a web browser in your local
5262 network look up an IPv4 address of "attacker.example.com",
5263 the attacker's DNS server would return a response like this:
5264 </p>
5266 <p>
5267 in the answer section.
5268 Since the rdata of this record (the IPv4 address) matches
5270 ignored.
5271 </p>
5272 <p>
5273 On the other hand, if the browser looks up a legitimate
5274 internal web server "www.example.net" and the
5275 following response is returned to
5277 </p>
5279 <p>
5280 it will be accepted since the owner name "www.example.net"
5282 "example.net".
5283 </p>
5284 <p>
5285 Note that this is not really an attack on the DNS per se.
5286 In fact, there is nothing wrong for an "external" name to
5287 be mapped to your "internal" IP address or domain name
5288 from the DNS point of view.
5289 It might actually be provided for a legitimate purpose,
5290 such as for debugging.
5291 As long as the mapping is provided by the correct owner,
5292 it is not possible or does not make sense to detect
5293 whether the intent of the mapping is legitimate or not
5294 within the DNS.
5295 The "rebinding" attack must primarily be protected at the
5296 application that uses the DNS.
5297 For a large site, however, it may be difficult to protect
5298 all possible applications at once.
5299 This filtering feature is provided only to help such an
5300 operational environment;
5301 it is generally discouraged to turn it on unless you are
5302 very sure you have no other choice and the attack is a
5303 real threat for your applications.
5304 </p>
5305 <p>
5306 Care should be particularly taken if you want to use this
5308 These addresses are obviously "internal", but many
5309 applications conventionally rely on a DNS mapping from
5310 some name to such an address.
5311 Filtering out DNS records containing this address
5312 spuriously can break such applications.
5313 </p>
5314 </div>
5315 </div>
5318 <a name="server_statement_grammar"></a><span><strong class="command">server</strong></span> Statement Grammar</h3></div></div></div>
5319 <pre class="programlisting"><span><strong class="command">server</strong></span> <em class="replaceable"><code>ip_addr[/prefixlen]</code></em> {
5321 [<span class="optional"> provide-ixfr <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5322 [<span class="optional"> request-ixfr <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5324 [<span class="optional"> edns-udp-size <em class="replaceable"><code>number</code></em> ; </span>]
5325 [<span class="optional"> max-udp-size <em class="replaceable"><code>number</code></em> ; </span>]
5327 [<span class="optional"> transfer-format <em class="replaceable"><code>( one-answer | many-answers )</code></em> ; ]</span>]
5328 [<span class="optional"> keys <em class="replaceable"><code>{ string ; [<span class="optional"> string ; [<span class="optional">...</span>]</span>] }</code></em> ; </span>]
5329 [<span class="optional"> transfer-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5330 [<span class="optional"> transfer-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5331 [<span class="optional"> notify-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5332 [<span class="optional"> notify-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5333 [<span class="optional"> query-source [<span class="optional"> address ( <em class="replaceable"><code>ip_addr</code></em> | <em class="replaceable"><code>*</code></em> ) </span>]
5334 [<span class="optional"> port ( <em class="replaceable"><code>ip_port</code></em> | <em class="replaceable"><code>*</code></em> ) </span>]; </span>]
5335 [<span class="optional"> query-source-v6 [<span class="optional"> address ( <em class="replaceable"><code>ip_addr</code></em> | <em class="replaceable"><code>*</code></em> ) </span>]
5336 [<span class="optional"> port ( <em class="replaceable"><code>ip_port</code></em> | <em class="replaceable"><code>*</code></em> ) </span>]; </span>]
5337 [<span class="optional"> use-queryport-pool <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5338 [<span class="optional"> queryport-pool-ports <em class="replaceable"><code>number</code></em>; </span>]
5339 [<span class="optional"> queryport-pool-updateinterval <em class="replaceable"><code>number</code></em>; </span>]
5340 };
5341 </pre>
5342 </div>
5345 <a name="server_statement_definition_and_usage"></a><span><strong class="command">server</strong></span> Statement Definition and
5346 Usage</h3></div></div></div>
5347 <p>
5349 characteristics
5350 to be associated with a remote name server. If a prefix length is
5351 specified, then a range of servers is covered. Only the most
5352 specific
5353 server clause applies regardless of the order in
5355 </p>
5356 <p>
5358 the top level of the
5360 statement.
5363 those
5364 apply to the view and any top-level ones are ignored.
5366 statements,
5368 used as
5369 defaults.
5370 </p>
5371 <p>
5372 If you discover that a remote server is giving out bad data,
5373 marking it as bogus will prevent further queries to it. The
5374 default
5375 value of <span><strong class="command">bogus</strong></span> is <span><strong class="command">no</strong></span>.
5376 </p>
5377 <p>
5379 whether
5380 the local server, acting as master, will respond with an
5381 incremental
5382 zone transfer when the given remote server, a slave, requests it.
5384 will be provided
5386 all transfers
5387 to the remote server will be non-incremental. If not set, the
5388 value
5390 view or
5391 global options block is used as a default.
5392 </p>
5393 <p>
5395 whether
5396 the local server, acting as a slave, will request incremental zone
5397 transfers from the given remote server, a master. If not set, the
5399 the view or
5400 global options block is used as a default.
5401 </p>
5402 <p>
5403 IXFR requests to servers that do not support IXFR will
5404 automatically
5405 fall back to AXFR. Therefore, there is no need to manually list
5406 which servers support IXFR and which ones do not; the global
5407 default
5411 to make it possible to disable the use of IXFR even when both
5412 master
5413 and slave claim to support it, for example if one of the servers
5414 is buggy and crashes or corrupts data when IXFR is used.
5415 </p>
5416 <p>
5418 the local server will attempt to use EDNS when communicating
5420 </p>
5421 <p>
5423 that is advertised by <span><strong class="command">named</strong></span> when querying the remote server.
5425 silently adjusted). This option is useful when you wish to
5426 advertises a different value to this server than the value you
5427 advertise globally, for example, when there is a firewall at the
5428 remote site that is blocking large replies.
5429 </p>
5430 <p>
5432 maximum EDNS UDP message size <span><strong class="command">named</strong></span> will send. Valid
5434 be silently adjusted). This option is useful when you
5435 know that there is a firewall that is blocking large
5437 </p>
5438 <p>
5439 The server supports two zone transfer methods. The first, <span><strong class="command">one-answer</strong></span>,
5440 uses one DNS message per resource record transferred. <span><strong class="command">many-answers</strong></span> packs
5441 as many resource records as possible into a message. <span><strong class="command">many-answers</strong></span> is
5442 more efficient, but is only known to be understood by <acronym class="acronym">BIND</acronym> 9, <acronym class="acronym">BIND</acronym>
5444 4.9.5. You can specify which method
5445 to use for a server with the <span><strong class="command">transfer-format</strong></span> option.
5448 specified
5450 used.
5451 </p>
5453 is used to limit the number of concurrent inbound zone
5454 transfers from the specified server. If no
5456 limit is set according to the
5458 </p>
5459 <p>
5461 <span><strong class="command">key_id</strong></span> defined by the <span><strong class="command">key</strong></span> statement,
5462 to be used for transaction security (TSIG, <a href="Bv9ARM.ch04.html#tsig" title="TSIG">the section called “TSIG”</a>)
5463 when talking to the remote server.
5464 When a request is sent to the remote server, a request signature
5465 will be generated using the key specified here and appended to the
5466 message. A request originating from the remote server is not
5467 required
5468 to be signed by this key.
5469 </p>
5470 <p>
5472 clause
5473 allows for multiple keys, only a single key per server is
5474 currently
5475 supported.
5476 </p>
5477 <p>
5480 the IPv4 and IPv6 source
5481 address to be used for zone transfer with the remote server,
5482 respectively.
5483 For an IPv4 remote server, only <span><strong class="command">transfer-source</strong></span> can
5484 be specified.
5485 Similarly, for an IPv6 remote server, only
5487 specified.
5488 For more details, see the description of
5491 <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
5492 </p>
5493 <p>
5496 IPv4 and IPv6 source address to be used for notify
5497 messages sent to remote servers, respectively. For an
5499 can be specified. Similarly, for an IPv6 remote server,
5501 </p>
5502 <p>
5505 IPv4 and IPv6 source address to be used for queries
5506 sent to remote servers, respectively. For an IPv4
5508 be specified. Similarly, for an IPv6 remote server,
5510 </p>
5511 </div>
5514 <a name="statschannels"></a><span><strong class="command">statistics-channels</strong></span> Statement Grammar</h3></div></div></div>
5515 <pre class="programlisting"><span><strong class="command">statistics-channels</strong></span> {
5516 [ inet ( ip_addr | * ) [ port ip_port ]
5518 [ inet ...; ]
5519 };
5520 </pre>
5521 </div>
5524 <a name="id2588103"></a><span><strong class="command">statistics-channels</strong></span> Statement Definition and
5525 Usage</h3></div></div></div>
5526 <p>
5528 declares communication channels to be used by system
5529 administrators to get access to statistics information of
5530 the name server.
5531 </p>
5532 <p>
5533 This statement intends to be flexible to support multiple
5534 communication protocols in the future, but currently only
5535 HTTP access is supported.
5536 It requires that BIND 9 be compiled with libxml2;
5538 still accepted even if it is built without the library,
5539 but any HTTP access will fail with an error.
5540 </p>
5541 <p>
5545 address. An <span><strong class="command">ip_addr</strong></span> of <code class="literal">*</code> (asterisk) is
5546 interpreted as the IPv4 wildcard address; connections will be
5547 accepted on any of the system's IPv4 addresses.
5548 To listen on the IPv6 wildcard address,
5549 use an <span><strong class="command">ip_addr</strong></span> of <code class="literal">::</code>.
5550 </p>
5551 <p>
5552 If no port is specified, port 80 is used for HTTP channels.
5555 </p>
5556 <p>
5557 The attempt of opening a statistics channel is
5559 Connections to the statistics channel are permitted based on the
5563 attempts from any address; since the statistics may
5564 contain sensitive internal information, it is highly
5565 recommended to restrict the source of connection requests
5566 appropriately.
5567 </p>
5568 <p>
5571 </p>
5572 </div>
5575 <a name="id2588326"></a><span><strong class="command">trusted-keys</strong></span> Statement Grammar</h3></div></div></div>
5577 <em class="replaceable"><code>string</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>string</code></em> ;
5578 [<span class="optional"> <em class="replaceable"><code>string</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>string</code></em> ; [<span class="optional">...</span>]</span>]
5579 };
5580 </pre>
5581 </div>
5584 <a name="id2588377"></a><span><strong class="command">trusted-keys</strong></span> Statement Definition
5585 and Usage</h3></div></div></div>
5586 <p>
5588 DNSSEC security roots. DNSSEC is described in <a href="Bv9ARM.ch04.html#DNSSEC" title="DNSSEC">the section called “DNSSEC”</a>. A security root is defined when the
5589 public key for a non-authoritative zone is known, but
5590 cannot be securely obtained through DNS, either because
5591 it is the DNS root zone or because its parent zone is
5592 unsigned. Once a key has been configured as a trusted
5593 key, it is treated as if it had been validated and
5594 proven secure. The resolver attempts DNSSEC validation
5595 on all DNS data in subdomains of a security root.
5596 </p>
5597 <p>
5598 All keys (and corresponding zones) listed in
5600 of what parent zones say. Similarly for all keys listed in
5602 used to validate the DNSKEY RRset. The parent's DS RRset
5603 will not be used.
5604 </p>
5605 <p>
5607 multiple key entries, each consisting of the key's
5608 domain name, flags, protocol, algorithm, and the Base-64
5609 representation of the key data.
5610 Spaces, tabs, newlines and carriage returns are ignored
5611 in the key data, so the configuration may be split up into
5612 multiple lines.
5613 </p>
5614 <p>
5617 set in both places, they are additive: keys defined at the top
5618 level are inherited by all views, but keys defined in a view
5619 are only used within that view.
5620 </p>
5621 </div>
5624 <a name="id2588424"></a><span><strong class="command">managed-keys</strong></span> Statement Grammar</h3></div></div></div>
5626 <em class="replaceable"><code>string</code></em> initial-key <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>string</code></em> ;
5627 [<span class="optional"> <em class="replaceable"><code>string</code></em> initial-key <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>string</code></em> ; [<span class="optional">...</span>]</span>]
5628 };
5629 </pre>
5630 </div>
5633 <a name="id2588475"></a><span><strong class="command">managed-keys</strong></span> Statement Definition
5634 and Usage</h3></div></div></div>
5635 <p>
5638 security roots. The difference is that
5640 automatically, without intervention from the resolver
5641 operator.
5642 </p>
5643 <p>
5644 Suppose, for example, that a zone's key-signing
5645 key was compromised, and the zone owner had to revoke and
5646 replace the key. A resolver which had the old key in a
5648 unable to validate this zone any longer; it would
5649 reply with a SERVFAIL response code. This would
5650 continue until the resolver operator had updated the
5652 </p>
5653 <p>
5654 If, however, the zone were listed in a
5656 zone owner could add a "stand-by" key to the zone in advance.
5659 would be able to transition smoothly to the new key. It would
5660 also recognize that the old key had been revoked, and cease
5661 using that key to validate answers, minimizing the damage that
5662 the compromised key could do.
5663 </p>
5664 <p>
5666 the keys to be managed, along with information about how the
5667 keys are to be initialized for the first time. The only
5668 initialization method currently supported (as of
5671 contain a copy of the initializing key. (Future releases may
5672 allow keys to be initialized by other methods, eliminating this
5673 requirement.)
5674 </p>
5675 <p>
5678 in the presence of the second field, containing the keyword
5681 trusted until they are removed from
5685 managed key database and start the RFC 5011 key maintenance
5686 process.
5687 </p>
5688 <p>
5691 DNSKEY RRset directly from the zone apex, and validates it
5693 statement. If the DNSKEY RRset is validly signed, then it is
5694 used as the basis for a new managed keys database.
5695 </p>
5696 <p>
5699 make sure RFC 5011 key maintenance has already been initialized
5700 for the specified domain, and if so, it simply moves on. The
5702 used to validate answers; it has been superseded by the key or
5703 keys stored in the managed keys database.
5704 </p>
5705 <p>
5709 zone will be removed from the managed keys database,
5710 and RFC 5011 key maintenance will no longer be used for that
5711 domain.
5712 </p>
5713 <p>
5718 </p>
5719 <p>
5720 In the current implementation, the managed keys database is
5721 stored as a master-format zone file called
5723 is changed, the zone is updated. As with any other dynamic
5724 zone, changes will be written into a journal file,
5726 to the master file as soon as possible afterward; in the case
5727 of the managed key database, this will usually occur within 30
5729 automatic key maintenace, those two files can be expected to
5730 exist in the working directory. (For this reason among others,
5731 the working directory should be always be writable by
5733 </p>
5734 <p>
5736 set to <strong class="userinput"><code>auto</code></strong>, <span><strong class="command">named</strong></span>
5737 will automatically initialize a managed key for the
5739 used to initialize the key maintenance process is built
5742 </p>
5743 </div>
5746 <a name="view_statement_grammar"></a><span><strong class="command">view</strong></span> Statement Grammar</h3></div></div></div>
5747 <pre class="programlisting"><span><strong class="command">view</strong></span> <em class="replaceable"><code>view_name</code></em>
5754 };
5755 </pre>
5756 </div>
5759 <a name="id2588848"></a><span><strong class="command">view</strong></span> Statement Definition and Usage</h3></div></div></div>
5760 <p>
5762 feature
5764 answer a DNS query differently
5765 depending on who is asking. It is particularly useful for
5766 implementing
5767 split DNS setups without having to run multiple servers.
5768 </p>
5769 <p>
5771 of the
5772 DNS namespace that will be seen by a subset of clients. A client
5773 matches
5774 a view if its source IP address matches the
5777 destination IP address matches
5779 view's
5781 specified, both
5782 <span><strong class="command">match-clients</strong></span> and <span><strong class="command">match-destinations</strong></span>
5783 default to matching all addresses. In addition to checking IP
5784 addresses
5785 <span><strong class="command">match-clients</strong></span> and <span><strong class="command">match-destinations</strong></span>
5787 mechanism for the
5788 client to select the view. A view can also be specified
5790 means that only recursive
5791 requests from matching clients will match that view.
5793 significant —
5794 a client request will be resolved in the context of the first
5796 </p>
5797 <p>
5799 statement will
5800 only be accessible to clients that match the <span><strong class="command">view</strong></span>.
5801 By defining a zone of the same name in multiple views, different
5802 zone data can be given to different clients, for example,
5803 "internal"
5804 and "external" clients in a split DNS setup.
5805 </p>
5806 <p>
5807 Many of the options given in the <span><strong class="command">options</strong></span> statement
5809 statement, and then
5810 apply only when resolving queries with that view. When no
5811 view-specific
5812 value is given, the value in the <span><strong class="command">options</strong></span> statement
5813 is used as a default. Also, zone options can have default values
5814 specified
5816 view-specific defaults
5817 take precedence over those in the <span><strong class="command">options</strong></span> statement.
5818 </p>
5819 <p>
5820 Views are class specific. If no class is given, class IN
5821 is assumed. Note that all non-IN views must contain a hint zone,
5822 since only the IN class has compiled-in default hints.
5823 </p>
5824 <p>
5826 the config
5827 file, a default view that matches any client is automatically
5828 created
5830 specified on
5831 the top level of the configuration file are considered to be part
5832 of
5834 statement will
5837 statements must
5839 </p>
5840 <p>
5841 Here is an example of a typical split DNS setup implemented
5843 </p>
5845 // This should match our internal networks.
5848 // Provide recursive service to internal
5849 // clients only.
5850 recursion yes;
5852 // Provide a complete view of the example.com
5853 // zone including addresses of internal hosts.
5854 zone "example.com" {
5855 type master;
5856 file "example-internal.db";
5857 };
5858 };
5860 view "external" {
5861 // Match all clients not matched by the
5862 // previous view.
5863 match-clients { any; };
5865 // Refuse recursive service to external clients.
5866 recursion no;
5868 // Provide a restricted view of the example.com
5869 // zone containing only publicly accessible hosts.
5870 zone "example.com" {
5871 type master;
5872 file "example-external.db";
5873 };
5874 };
5875 </pre>
5876 </div>
5880 Statement Grammar</h3></div></div></div>
5881 <pre class="programlisting"><span><strong class="command">zone</strong></span> <em class="replaceable"><code>zone_name</code></em> [<span class="optional"><em class="replaceable"><code>class</code></em></span>] {
5882 type master;
5883 [<span class="optional"> allow-query { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5884 [<span class="optional"> allow-query-on { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5885 [<span class="optional"> allow-transfer { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5886 [<span class="optional"> allow-update { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5887 [<span class="optional"> update-policy <em class="replaceable"><code>local</code></em> | { <em class="replaceable"><code>update_policy_rule</code></em> [<span class="optional">...</span>] }; </span>]
5888 [<span class="optional"> also-notify { <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ;
5889 [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
5890 [<span class="optional"> check-names (<code class="constant">warn</code>|<code class="constant">fail</code>|<code class="constant">ignore</code>) ; </span>]
5891 [<span class="optional"> check-mx (<code class="constant">warn</code>|<code class="constant">fail</code>|<code class="constant">ignore</code>) ; </span>]
5892 [<span class="optional"> check-wildcard <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5893 [<span class="optional"> check-integrity <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5894 [<span class="optional"> dialup <em class="replaceable"><code>dialup_option</code></em> ; </span>]
5896 [<span class="optional"> masterfile-format (<code class="constant">text</code>|<code class="constant">raw</code>) ; </span>]
5898 [<span class="optional"> max-journal-size <em class="replaceable"><code>size_spec</code></em>; </span>]
5899 [<span class="optional"> forward (<code class="constant">only</code>|<code class="constant">first</code>) ; </span>]
5900 [<span class="optional"> forwarders { [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
5902 [<span class="optional"> ixfr-from-differences <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5903 [<span class="optional"> ixfr-tmp-file <em class="replaceable"><code>string</code></em> ; </span>]
5904 [<span class="optional"> maintain-ixfr-base <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5905 [<span class="optional"> max-ixfr-log-size <em class="replaceable"><code>number</code></em> ; </span>]
5906 [<span class="optional"> max-transfer-idle-out <em class="replaceable"><code>number</code></em> ; </span>]
5907 [<span class="optional"> max-transfer-time-out <em class="replaceable"><code>number</code></em> ; </span>]
5908 [<span class="optional"> notify <em class="replaceable"><code>yes_or_no</code></em> | <em class="replaceable"><code>explicit</code></em> | <em class="replaceable"><code>master-only</code></em> ; </span>]
5909 [<span class="optional"> notify-delay <em class="replaceable"><code>seconds</code></em> ; </span>]
5910 [<span class="optional"> notify-to-soa <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5911 [<span class="optional"> pubkey <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>string</code></em> ; </span>]
5912 [<span class="optional"> notify-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5913 [<span class="optional"> notify-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5914 [<span class="optional"> zone-statistics <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5915 [<span class="optional"> sig-validity-interval <em class="replaceable"><code>number</code></em> [<span class="optional"><em class="replaceable"><code>number</code></em></span>] ; </span>]
5916 [<span class="optional"> sig-signing-nodes <em class="replaceable"><code>number</code></em> ; </span>]
5917 [<span class="optional"> sig-signing-signatures <em class="replaceable"><code>number</code></em> ; </span>]
5918 [<span class="optional"> sig-signing-type <em class="replaceable"><code>number</code></em> ; </span>]
5920 [<span class="optional"> min-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
5921 [<span class="optional"> max-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
5922 [<span class="optional"> min-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
5923 [<span class="optional"> max-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
5924 [<span class="optional"> key-directory <em class="replaceable"><code>path_name</code></em>; </span>]
5925 [<span class="optional"> auto-dnssec <code class="constant">allow</code>|<code class="constant">maintain</code>|<code class="constant">create</code>|<code class="constant">off</code>; </span>]
5926 [<span class="optional"> zero-no-soa-ttl <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5927 };
5929 zone <em class="replaceable"><code>zone_name</code></em> [<span class="optional"><em class="replaceable"><code>class</code></em></span>] {
5930 type slave;
5931 [<span class="optional"> allow-notify { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5932 [<span class="optional"> allow-query { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5933 [<span class="optional"> allow-query-on { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5934 [<span class="optional"> allow-transfer { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5935 [<span class="optional"> allow-update-forwarding { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5936 [<span class="optional"> update-check-ksk <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5937 [<span class="optional"> dnssec-dnskey-kskonly <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5938 [<span class="optional"> dnssec-secure-to-insecure <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5939 [<span class="optional"> try-tcp-refresh <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5940 [<span class="optional"> also-notify { <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ;
5941 [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
5942 [<span class="optional"> check-names (<code class="constant">warn</code>|<code class="constant">fail</code>|<code class="constant">ignore</code>) ; </span>]
5943 [<span class="optional"> dialup <em class="replaceable"><code>dialup_option</code></em> ; </span>]
5945 [<span class="optional"> masterfile-format (<code class="constant">text</code>|<code class="constant">raw</code>) ; </span>]
5947 [<span class="optional"> max-journal-size <em class="replaceable"><code>size_spec</code></em>; </span>]
5948 [<span class="optional"> forward (<code class="constant">only</code>|<code class="constant">first</code>) ; </span>]
5949 [<span class="optional"> forwarders { [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
5951 [<span class="optional"> ixfr-from-differences <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5952 [<span class="optional"> ixfr-tmp-file <em class="replaceable"><code>string</code></em> ; </span>]
5953 [<span class="optional"> maintain-ixfr-base <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5954 [<span class="optional"> masters [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] { ( <em class="replaceable"><code>masters_list</code></em> | <em class="replaceable"><code>ip_addr</code></em>
5956 [<span class="optional">key <em class="replaceable"><code>key</code></em></span>] ) ; [<span class="optional">...</span>] }; </span>]
5957 [<span class="optional"> max-ixfr-log-size <em class="replaceable"><code>number</code></em> ; </span>]
5958 [<span class="optional"> max-transfer-idle-in <em class="replaceable"><code>number</code></em> ; </span>]
5959 [<span class="optional"> max-transfer-idle-out <em class="replaceable"><code>number</code></em> ; </span>]
5960 [<span class="optional"> max-transfer-time-in <em class="replaceable"><code>number</code></em> ; </span>]
5961 [<span class="optional"> max-transfer-time-out <em class="replaceable"><code>number</code></em> ; </span>]
5962 [<span class="optional"> notify <em class="replaceable"><code>yes_or_no</code></em> | <em class="replaceable"><code>explicit</code></em> | <em class="replaceable"><code>master-only</code></em> ; </span>]
5963 [<span class="optional"> notify-delay <em class="replaceable"><code>seconds</code></em> ; </span>]
5964 [<span class="optional"> notify-to-soa <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5965 [<span class="optional"> pubkey <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>string</code></em> ; </span>]
5966 [<span class="optional"> transfer-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5967 [<span class="optional"> transfer-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5968 [<span class="optional"> alt-transfer-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5969 [<span class="optional"> alt-transfer-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>)
5970 [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5971 [<span class="optional"> use-alt-transfer-source <em class="replaceable"><code>yes_or_no</code></em>; </span>]
5972 [<span class="optional"> notify-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5973 [<span class="optional"> notify-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
5974 [<span class="optional"> zone-statistics <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5976 [<span class="optional"> min-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
5977 [<span class="optional"> max-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
5978 [<span class="optional"> min-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
5979 [<span class="optional"> max-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
5980 [<span class="optional"> multi-master <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5981 [<span class="optional"> zero-no-soa-ttl <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5982 };
5984 zone <em class="replaceable"><code>zone_name</code></em> [<span class="optional"><em class="replaceable"><code>class</code></em></span>] {
5985 type hint;
5987 [<span class="optional"> delegation-only <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5988 [<span class="optional"> check-names (<code class="constant">warn</code>|<code class="constant">fail</code>|<code class="constant">ignore</code>) ; </span>] // Not Implemented.
5989 };
5991 zone <em class="replaceable"><code>zone_name</code></em> [<span class="optional"><em class="replaceable"><code>class</code></em></span>] {
5992 type stub;
5993 [<span class="optional"> allow-query { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5994 [<span class="optional"> allow-query-on { <em class="replaceable"><code>address_match_list</code></em> }; </span>]
5995 [<span class="optional"> check-names (<code class="constant">warn</code>|<code class="constant">fail</code>|<code class="constant">ignore</code>) ; </span>]
5996 [<span class="optional"> dialup <em class="replaceable"><code>dialup_option</code></em> ; </span>]
5997 [<span class="optional"> delegation-only <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
5999 [<span class="optional"> masterfile-format (<code class="constant">text</code>|<code class="constant">raw</code>) ; </span>]
6000 [<span class="optional"> forward (<code class="constant">only</code>|<code class="constant">first</code>) ; </span>]
6001 [<span class="optional"> forwarders { [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
6002 [<span class="optional"> masters [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] { ( <em class="replaceable"><code>masters_list</code></em> | <em class="replaceable"><code>ip_addr</code></em>
6004 [<span class="optional">key <em class="replaceable"><code>key</code></em></span>] ) ; [<span class="optional">...</span>] }; </span>]
6005 [<span class="optional"> max-transfer-idle-in <em class="replaceable"><code>number</code></em> ; </span>]
6006 [<span class="optional"> max-transfer-time-in <em class="replaceable"><code>number</code></em> ; </span>]
6007 [<span class="optional"> pubkey <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>number</code></em> <em class="replaceable"><code>string</code></em> ; </span>]
6008 [<span class="optional"> transfer-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
6009 [<span class="optional"> transfer-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>)
6010 [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
6011 [<span class="optional"> alt-transfer-source (<em class="replaceable"><code>ip4_addr</code></em> | <code class="constant">*</code>) [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
6012 [<span class="optional"> alt-transfer-source-v6 (<em class="replaceable"><code>ip6_addr</code></em> | <code class="constant">*</code>)
6013 [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; </span>]
6014 [<span class="optional"> use-alt-transfer-source <em class="replaceable"><code>yes_or_no</code></em>; </span>]
6015 [<span class="optional"> zone-statistics <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
6017 [<span class="optional"> min-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
6018 [<span class="optional"> max-refresh-time <em class="replaceable"><code>number</code></em> ; </span>]
6019 [<span class="optional"> min-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
6020 [<span class="optional"> max-retry-time <em class="replaceable"><code>number</code></em> ; </span>]
6021 [<span class="optional"> multi-master <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
6022 };
6024 zone <em class="replaceable"><code>zone_name</code></em> [<span class="optional"><em class="replaceable"><code>class</code></em></span>] {
6025 type forward;
6026 [<span class="optional"> forward (<code class="constant">only</code>|<code class="constant">first</code>) ; </span>]
6027 [<span class="optional"> forwarders { [<span class="optional"> <em class="replaceable"><code>ip_addr</code></em> [<span class="optional">port <em class="replaceable"><code>ip_port</code></em></span>] ; ... </span>] }; </span>]
6028 [<span class="optional"> delegation-only <em class="replaceable"><code>yes_or_no</code></em> ; </span>]
6029 };
6031 zone <em class="replaceable"><code>zone_name</code></em> [<span class="optional"><em class="replaceable"><code>class</code></em></span>] {
6032 type delegation-only;
6033 };
6035 </pre>
6036 </div>
6039 <a name="id2590421"></a><span><strong class="command">zone</strong></span> Statement Definition and Usage</h3></div></div></div>
6044 <colgroup>
6045 <col>
6046 <col>
6047 </colgroup>
6048 <tbody>
6049 <tr>
6050 <td>
6051 <p>
6053 </p>
6054 </td>
6055 <td>
6056 <p>
6057 The server has a master copy of the data
6058 for the zone and will be able to provide authoritative
6059 answers for
6060 it.
6061 </p>
6062 </td>
6063 </tr>
6064 <tr>
6065 <td>
6066 <p>
6068 </p>
6069 </td>
6070 <td>
6071 <p>
6072 A slave zone is a replica of a master
6074 specifies one or more IP addresses
6075 of master servers that the slave contacts to update
6076 its copy of the zone.
6077 Masters list elements can also be names of other
6078 masters lists.
6079 By default, transfers are made from port 53 on the
6080 servers; this can
6081 be changed for all servers by specifying a port number
6082 before the
6083 list of IP addresses, or on a per-server basis after
6084 the IP address.
6085 Authentication to the master can also be done with
6086 per-server TSIG keys.
6087 If a file is specified, then the
6088 replica will be written to this file whenever the zone
6089 is changed,
6090 and reloaded from this file on a server restart. Use
6091 of a file is
6092 recommended, since it often speeds server startup and
6093 eliminates
6094 a needless waste of bandwidth. Note that for large
6095 numbers (in the
6096 tens or hundreds of thousands) of zones per server, it
6097 is best to
6098 use a two-level naming scheme for zone filenames. For
6099 example,
6101 the zone contents into a file called
6103 just the first two letters of the zone name. (Most
6104 operating systems
6105 behave very slowly if you put 100000 files into
6106 a single directory.)
6107 </p>
6108 </td>
6109 </tr>
6110 <tr>
6111 <td>
6112 <p>
6114 </p>
6115 </td>
6116 <td>
6117 <p>
6118 A stub zone is similar to a slave zone,
6119 except that it replicates only the NS records of a
6120 master zone instead
6121 of the entire zone. Stub zones are not a standard part
6122 of the DNS;
6124 </p>
6126 <p>
6127 Stub zones can be used to eliminate the need for glue
6128 NS record
6129 in a parent zone at the expense of maintaining a stub
6130 zone entry and
6132 This usage is not recommended for new configurations,
6133 and BIND 9
6134 supports it only in a limited way.
6136 transfers of a parent zone
6137 included the NS records from stub children of that
6138 zone. This meant
6139 that, in some cases, users could get away with
6140 configuring child stubs
6142 9 never mixes together zone data from different zones
6143 in this
6145 zone has child stub zones configured, all the slave
6146 servers for the
6147 parent zone also need to have the same child stub
6148 zones
6149 configured.
6150 </p>
6152 <p>
6153 Stub zones can also be used as a way of forcing the
6154 resolution
6155 of a given domain to use a particular set of
6156 authoritative servers.
6157 For example, the caching name servers on a private
6158 network using
6159 RFC1918 addressing may be configured with stub zones
6160 for
6162 to use a set of internal name servers as the
6163 authoritative
6164 servers for that domain.
6165 </p>
6166 </td>
6167 </tr>
6168 <tr>
6169 <td>
6170 <p>
6172 </p>
6173 </td>
6174 <td>
6175 <p>
6176 A "forward zone" is a way to configure
6177 forwarding on a per-domain basis. A <span><strong class="command">zone</strong></span> statement
6181 statement,
6182 which will apply to queries within the domain given by
6183 the zone
6185 statement is present or
6187 forwarding will be done for the domain, canceling the
6188 effects of
6190 if you want to use this type of zone to change the
6191 behavior of the
6193 (that is, "forward first"
6194 to, then "forward only", or vice versa, but want to
6195 use the same
6196 servers as set globally) you need to re-specify the
6197 global forwarders.
6198 </p>
6199 </td>
6200 </tr>
6201 <tr>
6202 <td>
6203 <p>
6205 </p>
6206 </td>
6207 <td>
6208 <p>
6209 The initial set of root name servers is
6210 specified using a "hint zone". When the server starts
6211 up, it uses
6212 the root hints to find a root name server and get the
6213 most recent
6214 list of root name servers. If no hint zone is
6215 specified for class
6216 IN, the server uses a compiled-in default set of root
6217 servers hints.
6218 Classes other than IN have no built-in defaults hints.
6219 </p>
6220 </td>
6221 </tr>
6222 <tr>
6223 <td>
6224 <p>
6226 </p>
6227 </td>
6228 <td>
6229 <p>
6230 This is used to enforce the delegation-only
6231 status of infrastructure zones (e.g. COM,
6232 NET, ORG). Any answer that is received
6233 without an explicit or implicit delegation
6234 in the authority section will be treated
6235 as NXDOMAIN. This does not apply to the
6236 zone apex. This should not be applied to
6237 leaf zones.
6238 </p>
6239 <p>
6241 effect on answers received from forwarders.
6242 </p>
6243 <p>
6244 See caveats in <a href="Bv9ARM.ch06.html#root_delegation_only"><span><strong class="command">root-delegation-only</strong></span></a>.
6245 </p>
6246 </td>
6247 </tr>
6248 </tbody>
6249 </table></div>
6250 </div>
6254 <p>
6255 The zone's name may optionally be followed by a class. If
6256 a class is not specified, class <code class="literal">IN</code> (for <code class="varname">Internet</code>),
6257 is assumed. This is correct for the vast majority of cases.
6258 </p>
6259 <p>
6261 named for an information service from MIT's Project Athena. It
6262 is
6263 used to share information about various systems databases, such
6264 as users, groups, printers and so on. The keyword
6266 a synonym for hesiod.
6267 </p>
6268 <p>
6269 Another MIT development is Chaosnet, a LAN protocol created
6270 in the mid-1970s. Zone data for it can be specified with the <code class="literal">CHAOS</code> class.
6271 </p>
6272 </div>
6278 <dd><p>
6279 See the description of
6280 <span><strong class="command">allow-notify</strong></span> in <a href="Bv9ARM.ch06.html#access_control" title="Access Control">the section called “Access Control”</a>.
6281 </p></dd>
6283 <dd><p>
6284 See the description of
6285 <span><strong class="command">allow-query</strong></span> in <a href="Bv9ARM.ch06.html#access_control" title="Access Control">the section called “Access Control”</a>.
6286 </p></dd>
6287 <dt><span class="term"><span><strong class="command">allow-query-on</strong></span></span></dt>
6288 <dd><p>
6289 See the description of
6290 <span><strong class="command">allow-query-on</strong></span> in <a href="Bv9ARM.ch06.html#access_control" title="Access Control">the section called “Access Control”</a>.
6291 </p></dd>
6292 <dt><span class="term"><span><strong class="command">allow-transfer</strong></span></span></dt>
6293 <dd><p>
6295 in <a href="Bv9ARM.ch06.html#access_control" title="Access Control">the section called “Access Control”</a>.
6296 </p></dd>
6298 <dd><p>
6300 in <a href="Bv9ARM.ch06.html#access_control" title="Access Control">the section called “Access Control”</a>.
6301 </p></dd>
6303 <dd><p>
6304 Specifies a "Simple Secure Update" policy. See
6305 <a href="Bv9ARM.ch06.html#dynamic_update_policies" title="Dynamic Update Policies">the section called “Dynamic Update Policies”</a>.
6306 </p></dd>
6307 <dt><span class="term"><span><strong class="command">allow-update-forwarding</strong></span></span></dt>
6308 <dd><p>
6310 in <a href="Bv9ARM.ch06.html#access_control" title="Access Control">the section called “Access Control”</a>.
6311 </p></dd>
6313 <dd><p>
6315 is
6316 active for this zone. The set of machines that will
6317 receive a
6319 for this zone is made up of all the listed name servers
6320 (other than
6321 the primary master) for the zone plus any IP addresses
6322 specified
6324 may be specified
6326 address to send the notify
6327 messages to a port other than the default of 53.
6329 meaningful for stub zones.
6330 The default is the empty list.
6331 </p></dd>
6333 <dd><p>
6334 This option is used to restrict the character set and
6335 syntax of
6336 certain domain names in master files and/or DNS responses
6337 received from the
6338 network. The default varies according to zone type. For <span><strong class="command">master</strong></span> zones the default is <span><strong class="command">fail</strong></span>. For <span><strong class="command">slave</strong></span>
6341 </p></dd>
6343 <dd><p>
6344 See the description of
6345 <span><strong class="command">check-mx</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6346 </p></dd>
6347 <dt><span class="term"><span><strong class="command">check-wildcard</strong></span></span></dt>
6348 <dd><p>
6349 See the description of
6350 <span><strong class="command">check-wildcard</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6351 </p></dd>
6352 <dt><span class="term"><span><strong class="command">check-integrity</strong></span></span></dt>
6353 <dd><p>
6354 See the description of
6355 <span><strong class="command">check-integrity</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6356 </p></dd>
6358 <dd><p>
6359 See the description of
6360 <span><strong class="command">check-sibling</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6361 </p></dd>
6362 <dt><span class="term"><span><strong class="command">zero-no-soa-ttl</strong></span></span></dt>
6363 <dd><p>
6364 See the description of
6365 <span><strong class="command">zero-no-soa-ttl</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6366 </p></dd>
6367 <dt><span class="term"><span><strong class="command">update-check-ksk</strong></span></span></dt>
6368 <dd><p>
6369 See the description of
6370 <span><strong class="command">update-check-ksk</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6371 </p></dd>
6372 <dt><span class="term"><span><strong class="command">dnssec-dnskey-kskonly</strong></span></span></dt>
6373 <dd><p>
6374 See the description of
6375 <span><strong class="command">dnssec-dnskey-kskonly</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6376 </p></dd>
6377 <dt><span class="term"><span><strong class="command">try-tcp-refresh</strong></span></span></dt>
6378 <dd><p>
6379 See the description of
6380 <span><strong class="command">try-tcp-refresh</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6381 </p></dd>
6383 <dd>
6384 <p>
6385 Specify the type of database to be used for storing the
6386 zone data. The string following the <span><strong class="command">database</strong></span> keyword
6387 is interpreted as a list of whitespace-delimited words.
6388 The first word
6389 identifies the database type, and any subsequent words are
6390 passed
6391 as arguments to the database to be interpreted in a way
6392 specific
6393 to the database type.
6394 </p>
6395 <p>
6397 native in-memory
6398 red-black-tree database. This database does not take
6399 arguments.
6400 </p>
6401 <p>
6402 Other values are possible if additional database drivers
6403 have been linked into the server. Some sample drivers are
6404 included
6405 with the distribution but none are linked in by default.
6406 </p>
6407 </dd>
6409 <dd><p>
6410 See the description of
6411 <span><strong class="command">dialup</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6412 </p></dd>
6413 <dt><span class="term"><span><strong class="command">delegation-only</strong></span></span></dt>
6414 <dd>
6415 <p>
6416 The flag only applies to hint and stub zones. If set
6418 treated as if it is also a delegation-only type zone.
6419 </p>
6420 <p>
6421 See caveats in <a href="Bv9ARM.ch06.html#root_delegation_only"><span><strong class="command">root-delegation-only</strong></span></a>.
6422 </p>
6423 </dd>
6425 <dd><p>
6426 Only meaningful if the zone has a forwarders
6428 the lookup to fail
6429 after trying the forwarders and getting no answer, while <span><strong class="command">first</strong></span> would
6430 allow a normal lookup to be tried.
6431 </p></dd>
6433 <dd><p>
6434 Used to override the list of global forwarders.
6435 If it is not specified in a zone of type <span><strong class="command">forward</strong></span>,
6436 no forwarding is done for the zone and the global options are
6437 not used.
6438 </p></dd>
6440 <dd><p>
6442 specify the name
6443 of the transaction log (journal) file for dynamic update
6444 and IXFR.
6446 and constructs the name of the journal
6448 to the name of the
6449 zone file.
6450 </p></dd>
6452 <dd><p>
6455 </p></dd>
6457 <dd><p>
6458 Allow the default journal's filename to be overridden.
6460 This is applicable to <span><strong class="command">master</strong></span> and <span><strong class="command">slave</strong></span> zones.
6461 </p></dd>
6462 <dt><span class="term"><span><strong class="command">max-journal-size</strong></span></span></dt>
6463 <dd><p>
6464 See the description of
6465 <span><strong class="command">max-journal-size</strong></span> in <a href="Bv9ARM.ch06.html#server_resource_limits" title="Server Resource Limits">the section called “Server Resource Limits”</a>.
6466 </p></dd>
6467 <dt><span class="term"><span><strong class="command">max-transfer-time-in</strong></span></span></dt>
6468 <dd><p>
6469 See the description of
6470 <span><strong class="command">max-transfer-time-in</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
6471 </p></dd>
6472 <dt><span class="term"><span><strong class="command">max-transfer-idle-in</strong></span></span></dt>
6473 <dd><p>
6474 See the description of
6475 <span><strong class="command">max-transfer-idle-in</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
6476 </p></dd>
6477 <dt><span class="term"><span><strong class="command">max-transfer-time-out</strong></span></span></dt>
6478 <dd><p>
6479 See the description of
6480 <span><strong class="command">max-transfer-time-out</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
6481 </p></dd>
6482 <dt><span class="term"><span><strong class="command">max-transfer-idle-out</strong></span></span></dt>
6483 <dd><p>
6484 See the description of
6485 <span><strong class="command">max-transfer-idle-out</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
6486 </p></dd>
6488 <dd><p>
6489 See the description of
6490 <span><strong class="command">notify</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6491 </p></dd>
6493 <dd><p>
6494 See the description of
6495 <span><strong class="command">notify-delay</strong></span> in <a href="Bv9ARM.ch06.html#tuning" title="Tuning">the section called “Tuning”</a>.
6496 </p></dd>
6498 <dd><p>
6499 See the description of
6501 <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6502 </p></dd>
6504 <dd><p>
6506 intended for specifying
6507 a public zone key for verification of signatures in DNSSEC
6508 signed
6509 zones when they are loaded from disk. <acronym class="acronym">BIND</acronym> 9 does not verify signatures
6510 on load and ignores the option.
6511 </p></dd>
6512 <dt><span class="term"><span><strong class="command">zone-statistics</strong></span></span></dt>
6513 <dd><p>
6515 statistical
6516 information for this zone, which can be dumped to the
6518 the server options.
6519 </p></dd>
6520 <dt><span class="term"><span><strong class="command">sig-validity-interval</strong></span></span></dt>
6521 <dd><p>
6522 See the description of
6523 <span><strong class="command">sig-validity-interval</strong></span> in <a href="Bv9ARM.ch06.html#tuning" title="Tuning">the section called “Tuning”</a>.
6524 </p></dd>
6525 <dt><span class="term"><span><strong class="command">sig-signing-nodes</strong></span></span></dt>
6526 <dd><p>
6527 See the description of
6528 <span><strong class="command">sig-signing-nodes</strong></span> in <a href="Bv9ARM.ch06.html#tuning" title="Tuning">the section called “Tuning”</a>.
6529 </p></dd>
6530 <dt><span class="term"><span><strong class="command">sig-signing-signatures</strong></span></span></dt>
6531 <dd><p>
6532 See the description of
6533 <span><strong class="command">sig-signing-signatures</strong></span> in <a href="Bv9ARM.ch06.html#tuning" title="Tuning">the section called “Tuning”</a>.
6534 </p></dd>
6535 <dt><span class="term"><span><strong class="command">sig-signing-type</strong></span></span></dt>
6536 <dd><p>
6537 See the description of
6538 <span><strong class="command">sig-signing-type</strong></span> in <a href="Bv9ARM.ch06.html#tuning" title="Tuning">the section called “Tuning”</a>.
6539 </p></dd>
6540 <dt><span class="term"><span><strong class="command">transfer-source</strong></span></span></dt>
6541 <dd><p>
6542 See the description of
6543 <span><strong class="command">transfer-source</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
6544 </p></dd>
6545 <dt><span class="term"><span><strong class="command">transfer-source-v6</strong></span></span></dt>
6546 <dd><p>
6547 See the description of
6548 <span><strong class="command">transfer-source-v6</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
6549 </p></dd>
6550 <dt><span class="term"><span><strong class="command">alt-transfer-source</strong></span></span></dt>
6551 <dd><p>
6552 See the description of
6553 <span><strong class="command">alt-transfer-source</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
6554 </p></dd>
6555 <dt><span class="term"><span><strong class="command">alt-transfer-source-v6</strong></span></span></dt>
6556 <dd><p>
6557 See the description of
6558 <span><strong class="command">alt-transfer-source-v6</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
6559 </p></dd>
6560 <dt><span class="term"><span><strong class="command">use-alt-transfer-source</strong></span></span></dt>
6561 <dd><p>
6562 See the description of
6563 <span><strong class="command">use-alt-transfer-source</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
6564 </p></dd>
6566 <dd><p>
6567 See the description of
6568 <span><strong class="command">notify-source</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
6569 </p></dd>
6570 <dt><span class="term"><span><strong class="command">notify-source-v6</strong></span></span></dt>
6571 <dd><p>
6572 See the description of
6573 <span><strong class="command">notify-source-v6</strong></span> in <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>.
6574 </p></dd>
6575 <dt>
6576 <span class="term"><span><strong class="command">min-refresh-time</strong></span>, </span><span class="term"><span><strong class="command">max-refresh-time</strong></span>, </span><span class="term"><span><strong class="command">min-retry-time</strong></span>, </span><span class="term"><span><strong class="command">max-retry-time</strong></span></span>
6577 </dt>
6578 <dd><p>
6579 See the description in <a href="Bv9ARM.ch06.html#tuning" title="Tuning">the section called “Tuning”</a>.
6580 </p></dd>
6581 <dt><span class="term"><span><strong class="command">ixfr-from-differences</strong></span></span></dt>
6582 <dd><p>
6583 See the description of
6584 <span><strong class="command">ixfr-from-differences</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6588 available at the zone level.)
6589 </p></dd>
6591 <dd><p>
6592 See the description of
6593 <span><strong class="command">key-directory</strong></span> in <a href="Bv9ARM.ch06.html#options" title="options Statement Definition and
6594 Usage">the section called “<span><strong class="command">options</strong></span> Statement Definition and
6596 </p></dd>
6598 <dd>
6599 <p>
6600 Zones configured for dynamic DNS may also use this
6601 option to allow varying levels of autonatic DNSSEC key
6602 management. There are four possible settings:
6603 </p>
6604 <p>
6606 keys to be updated and the zone re-signed whenever the
6609 </p>
6610 <p>
6612 above, but also automatically adjusts the zone's DNSSEC
6613 keys on schedule, according to the keys' timing metadata
6614 (see <a href="man.dnssec-keygen.html" title="dnssec-keygen"><span class="refentrytitle"><span class="application">dnssec-keygen</span></span>(8)</a> and
6615 <a href="man.dnssec-settime.html" title="dnssec-settime"><span class="refentrytitle"><span class="application">dnssec-settime</span></span>(8)</a>).
6616 </p>
6617 <p>
6620 to create new keys in the key repository when needed.
6621 (NOTE: This option is not yet implemented; the syntax is
6622 being reserved for future use.)
6623 </p>
6624 <p>
6626 </p>
6627 </dd>
6629 <dd><p>
6631 <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6632 </p></dd>
6633 <dt><span class="term"><span><strong class="command">masterfile-format</strong></span></span></dt>
6634 <dd><p>
6636 in <a href="Bv9ARM.ch06.html#tuning" title="Tuning">the section called “Tuning”</a>.
6637 </p></dd>
6638 <dt><span class="term"><span><strong class="command">dnssec-secure-to-insecure</strong></span></span></dt>
6639 <dd><p>
6640 See the description of
6641 <span><strong class="command">dnssec-secure-to-insecure</strong></span> in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a>.
6642 </p></dd>
6643 </dl></div>
6644 </div>
6649 methods of granting clients the right to perform
6650 dynamic updates to a zone, configured by the
6653 </p>
6654 <p>
6657 It grants given clients the permission to update any
6658 record of any name in the zone.
6659 </p>
6660 <p>
6662 allows more fine-grained control over what updates are
6663 allowed. A set of rules is specified, where each rule
6664 either grants or denies permissions for one or more
6665 names to be updated by one or more identities. If
6666 the dynamic update request message is signed (that is,
6667 it includes either a TSIG or SIG(0) record), the
6668 identity of the signer can be determined.
6669 </p>
6670 <p>
6672 zone option, and are only meaningful for master zones.
6674 is present, it is a configuration error for the
6677 only examines the signer of a message; the source
6678 address is not relevant.
6679 </p>
6680 <p>
6682 rule which can be switched on with the command
6684 Switching on this rule in a zone causes
6686 key and place it in a file, and to allow that key
6687 to update the zone. (By default, the file is
6689 name is "local-ddns" and the key algorithm is HMAC-SHA256,
6690 but these values are configurable with the
6694 </p>
6695 <p>
6696 A client running on the local system, and with appropriate
6697 permissions, may read that file and use the key to sign update
6698 requests. The zone's update policy will be set to allow that
6699 key to change any record within the zone. Assuming the
6700 key name is "local-ddns", this policy is equivalent to:
6701 </p>
6703 </pre>
6704 <p>
6706 requests to localhost, and signs them using the session key.
6707 </p>
6708 <p>
6709 Other rule definitions look like this:
6710 </p>
6712 ( <span><strong class="command">grant</strong></span> | <span><strong class="command">deny</strong></span> ) <em class="replaceable"><code>identity</code></em> <em class="replaceable"><code>nametype</code></em> [<span class="optional"> <em class="replaceable"><code>name</code></em> </span>] [<span class="optional"> <em class="replaceable"><code>types</code></em> </span>]
6713 </pre>
6714 <p>
6715 Each rule grants or denies privileges. Once a message has
6716 successfully matched a rule, the operation is immediately
6717 granted or denied and no further rules are examined. A rule
6718 is matched when the signer matches the identity field, the
6719 name matches the name field in accordance with the nametype
6720 field, and the type matches the types specified in the type
6721 field.
6722 </p>
6723 <p>
6726 reverse mapping / prefix conversion must match the identity
6727 field.
6728 </p>
6729 <p>
6730 The identity field specifies a name or a wildcard
6731 name. Normally, this is the name of the TSIG or
6732 SIG(0) key used to sign the update request. When a
6733 TKEY exchange has been used to create a shared secret,
6734 the identity of the shared secret is the same as the
6735 identity of the key used to authenticate the TKEY
6736 exchange. TKEY is also the negotiation method used
6737 by GSS-TSIG, which establishes an identity that is
6738 the Kerberos principal of the client, such as
6741 a wildcard name, it is subject to DNS wildcard
6742 expansion, so the rule will apply to multiple identities.
6744 contain a fully-qualified domain name.
6745 </p>
6746 <p>
6748 values:
6757 </p>
6759 <colgroup>
6760 <col>
6761 <col>
6762 </colgroup>
6763 <tbody>
6764 <tr>
6765 <td>
6766 <p>
6768 </p>
6769 </td>
6770 <td>
6771 <p>
6772 Exact-match semantics. This rule matches
6773 when the name being updated is identical
6774 to the contents of the
6776 </p>
6777 </td>
6778 </tr>
6779 <tr>
6780 <td>
6781 <p>
6783 </p>
6784 </td>
6785 <td>
6786 <p>
6787 This rule matches when the name being updated
6788 is a subdomain of, or identical to, the
6790 field.
6791 </p>
6792 </td>
6793 </tr>
6794 <tr>
6795 <td>
6796 <p>
6798 </p>
6799 </td>
6800 <td>
6801 <p>
6802 This rule is similar to subdomain, except that
6803 it matches when the name being updated is a
6804 subdomain of the zone in which the
6806 appears. This obviates the need to type the zone
6807 name twice, and enables the use of a standard
6809 multiple zones without modification.
6810 </p>
6811 <p>
6812 When this rule is used, the
6814 </p>
6815 </td>
6816 </tr>
6817 <tr>
6818 <td>
6819 <p>
6821 </p>
6822 </td>
6823 <td>
6824 <p>
6826 is subject to DNS wildcard expansion, and
6827 this rule matches when the name being updated
6828 name is a valid expansion of the wildcard.
6829 </p>
6830 </td>
6831 </tr>
6832 <tr>
6833 <td>
6834 <p>
6836 </p>
6837 </td>
6838 <td>
6839 <p>
6840 This rule matches when the name being updated
6841 matches the contents of the
6844 is ignored, but should be the same as the
6847 most useful when allowing using one key per
6848 name to update, where the key has the same
6849 name as the name to be updated. The
6852 this case.
6853 </p>
6854 </td>
6855 </tr>
6856 <tr>
6857 <td>
6858 <p>
6860 </p>
6861 </td>
6862 <td>
6863 <p>
6866 can also be updated.
6867 </p>
6868 </td>
6869 </tr>
6870 <tr>
6871 <td>
6872 <p>
6874 </p>
6875 </td>
6876 <td>
6877 <p>
6879 except that only subdomains of
6881 </p>
6882 </td>
6883 </tr>
6884 <tr>
6885 <td>
6886 <p>
6888 </p>
6889 </td>
6890 <td>
6891 <p>
6892 Allow updates that have been sent via TCP and
6893 for which the standard mapping from the initiating
6894 IP address into the IN-ADDR.ARPA and IP6.ARPA
6895 namespaces match the name to be updated.
6896 </p>
6899 It is theoretically possible to spoof these TCP
6900 sessions.
6901 </div>
6902 </td>
6903 </tr>
6904 <tr>
6905 <td>
6906 <p>
6908 </p>
6909 </td>
6910 <td>
6911 <p>
6912 Allow the 6to4 prefix to be update by any TCP
6913 connection from the 6to4 network or from the
6914 corresponding IPv4 address. This is intended
6915 to allow NS or DNAME RRsets to be added to the
6916 reverse tree.
6917 </p>
6920 It is theoretically possible to spoof these TCP
6921 sessions.
6922 </div>
6923 </td>
6924 </tr>
6925 </tbody>
6926 </table></div>
6927 <p>
6929 field must
6930 specify a fully-qualified domain name.
6931 </p>
6932 <p>
6933 If no types are explicitly specified, this rule matches
6934 all types except RRSIG, NS, SOA, NSEC and NSEC3. Types
6935 may be specified by name, including "ANY" (ANY matches
6936 all types except NSEC and NSEC3, which can never be
6937 updated). Note that when an attempt is made to delete
6938 all records associated with a name, the rules are
6939 checked for each existing record type.
6940 </p>
6941 </div>
6942 </div>
6943 </div>
6949 <a name="types_of_resource_records_and_when_to_use_them"></a>Types of Resource Records and When to Use Them</h3></div></div></div>
6950 <p>
6951 This section, largely borrowed from RFC 1034, describes the
6952 concept of a Resource Record (RR) and explains when each is used.
6953 Since the publication of RFC 1034, several new RRs have been
6954 identified
6955 and implemented in the DNS. These are also included.
6956 </p>
6960 <p>
6961 A domain name identifies a node. Each node has a set of
6962 resource information, which may be empty. The set of resource
6963 information associated with a particular name is composed of
6964 separate RRs. The order of RRs in a set is not significant and
6965 need not be preserved by name servers, resolvers, or other
6966 parts of the DNS. However, sorting of multiple RRs is
6967 permitted for optimization purposes, for example, to specify
6968 that a particular nearby server be tried first. See <a href="Bv9ARM.ch06.html#the_sortlist_statement" title="The sortlist Statement">the section called “The <span><strong class="command">sortlist</strong></span> Statement”</a> and <a href="Bv9ARM.ch06.html#rrset_ordering" title="RRset Ordering">the section called “RRset Ordering”</a>.
6969 </p>
6970 <p>
6971 The components of a Resource Record are:
6972 </p>
6974 <colgroup>
6975 <col>
6976 <col>
6977 </colgroup>
6978 <tbody>
6979 <tr>
6980 <td>
6981 <p>
6982 owner name
6983 </p>
6984 </td>
6985 <td>
6986 <p>
6987 The domain name where the RR is found.
6988 </p>
6989 </td>
6990 </tr>
6991 <tr>
6992 <td>
6993 <p>
6994 type
6995 </p>
6996 </td>
6997 <td>
6998 <p>
6999 An encoded 16-bit value that specifies
7000 the type of the resource record.
7001 </p>
7002 </td>
7003 </tr>
7004 <tr>
7005 <td>
7006 <p>
7007 TTL
7008 </p>
7009 </td>
7010 <td>
7011 <p>
7012 The time-to-live of the RR. This field
7013 is a 32-bit integer in units of seconds, and is
7014 primarily used by
7015 resolvers when they cache RRs. The TTL describes how
7016 long a RR can
7017 be cached before it should be discarded.
7018 </p>
7019 </td>
7020 </tr>
7021 <tr>
7022 <td>
7023 <p>
7024 class
7025 </p>
7026 </td>
7027 <td>
7028 <p>
7029 An encoded 16-bit value that identifies
7030 a protocol family or instance of a protocol.
7031 </p>
7032 </td>
7033 </tr>
7034 <tr>
7035 <td>
7036 <p>
7037 RDATA
7038 </p>
7039 </td>
7040 <td>
7041 <p>
7042 The resource data. The format of the
7043 data is type (and sometimes class) specific.
7044 </p>
7045 </td>
7046 </tr>
7047 </tbody>
7048 </table></div>
7049 <p>
7051 </p>
7053 <colgroup>
7054 <col>
7055 <col>
7056 </colgroup>
7057 <tbody>
7058 <tr>
7059 <td>
7060 <p>
7061 A
7062 </p>
7063 </td>
7064 <td>
7065 <p>
7066 A host address. In the IN class, this is a
7068 </p>
7069 </td>
7070 </tr>
7071 <tr>
7072 <td>
7073 <p>
7074 AAAA
7075 </p>
7076 </td>
7077 <td>
7078 <p>
7079 IPv6 address. Described in RFC 1886.
7080 </p>
7081 </td>
7082 </tr>
7083 <tr>
7084 <td>
7085 <p>
7086 A6
7087 </p>
7088 </td>
7089 <td>
7090 <p>
7091 IPv6 address. This can be a partial
7092 address (a suffix) and an indirection to the name
7093 where the rest of the
7094 address (the prefix) can be found. Experimental.
7095 Described in RFC 2874.
7096 </p>
7097 </td>
7098 </tr>
7099 <tr>
7100 <td>
7101 <p>
7102 AFSDB
7103 </p>
7104 </td>
7105 <td>
7106 <p>
7107 Location of AFS database servers.
7108 Experimental. Described in RFC 1183.
7109 </p>
7110 </td>
7111 </tr>
7112 <tr>
7113 <td>
7114 <p>
7115 APL
7116 </p>
7117 </td>
7118 <td>
7119 <p>
7120 Address prefix list. Experimental.
7121 Described in RFC 3123.
7122 </p>
7123 </td>
7124 </tr>
7125 <tr>
7126 <td>
7127 <p>
7128 CERT
7129 </p>
7130 </td>
7131 <td>
7132 <p>
7133 Holds a digital certificate.
7134 Described in RFC 2538.
7135 </p>
7136 </td>
7137 </tr>
7138 <tr>
7139 <td>
7140 <p>
7141 CNAME
7142 </p>
7143 </td>
7144 <td>
7145 <p>
7146 Identifies the canonical name of an alias.
7147 Described in RFC 1035.
7148 </p>
7149 </td>
7150 </tr>
7151 <tr>
7152 <td>
7153 <p>
7154 DHCID
7155 </p>
7156 </td>
7157 <td>
7158 <p>
7159 Is used for identifying which DHCP client is
7160 associated with this name. Described in RFC 4701.
7161 </p>
7162 </td>
7163 </tr>
7164 <tr>
7165 <td>
7166 <p>
7167 DNAME
7168 </p>
7169 </td>
7170 <td>
7171 <p>
7172 Replaces the domain name specified with
7173 another name to be looked up, effectively aliasing an
7174 entire
7175 subtree of the domain name space rather than a single
7176 record
7177 as in the case of the CNAME RR.
7178 Described in RFC 2672.
7179 </p>
7180 </td>
7181 </tr>
7182 <tr>
7183 <td>
7184 <p>
7185 DNSKEY
7186 </p>
7187 </td>
7188 <td>
7189 <p>
7190 Stores a public key associated with a signed
7191 DNS zone. Described in RFC 4034.
7192 </p>
7193 </td>
7194 </tr>
7195 <tr>
7196 <td>
7197 <p>
7198 DS
7199 </p>
7200 </td>
7201 <td>
7202 <p>
7203 Stores the hash of a public key associated with a
7204 signed DNS zone. Described in RFC 4034.
7205 </p>
7206 </td>
7207 </tr>
7208 <tr>
7209 <td>
7210 <p>
7211 GPOS
7212 </p>
7213 </td>
7214 <td>
7215 <p>
7216 Specifies the global position. Superseded by LOC.
7217 </p>
7218 </td>
7219 </tr>
7220 <tr>
7221 <td>
7222 <p>
7223 HINFO
7224 </p>
7225 </td>
7226 <td>
7227 <p>
7228 Identifies the CPU and OS used by a host.
7229 Described in RFC 1035.
7230 </p>
7231 </td>
7232 </tr>
7233 <tr>
7234 <td>
7235 <p>
7236 IPSECKEY
7237 </p>
7238 </td>
7239 <td>
7240 <p>
7241 Provides a method for storing IPsec keying material in
7242 DNS. Described in RFC 4025.
7243 </p>
7244 </td>
7245 </tr>
7246 <tr>
7247 <td>
7248 <p>
7249 ISDN
7250 </p>
7251 </td>
7252 <td>
7253 <p>
7254 Representation of ISDN addresses.
7255 Experimental. Described in RFC 1183.
7256 </p>
7257 </td>
7258 </tr>
7259 <tr>
7260 <td>
7261 <p>
7262 KEY
7263 </p>
7264 </td>
7265 <td>
7266 <p>
7267 Stores a public key associated with a
7268 DNS name. Used in original DNSSEC; replaced
7269 by DNSKEY in DNSSECbis, but still used with
7271 </p>
7272 </td>
7273 </tr>
7274 <tr>
7275 <td>
7276 <p>
7277 KX
7278 </p>
7279 </td>
7280 <td>
7281 <p>
7282 Identifies a key exchanger for this
7283 DNS name. Described in RFC 2230.
7284 </p>
7285 </td>
7286 </tr>
7287 <tr>
7288 <td>
7289 <p>
7290 LOC
7291 </p>
7292 </td>
7293 <td>
7294 <p>
7295 For storing GPS info. Described in RFC 1876.
7296 Experimental.
7297 </p>
7298 </td>
7299 </tr>
7300 <tr>
7301 <td>
7302 <p>
7303 MX
7304 </p>
7305 </td>
7306 <td>
7307 <p>
7308 Identifies a mail exchange for the domain with
7309 a 16-bit preference value (lower is better)
7310 followed by the host name of the mail exchange.
7312 </p>
7313 </td>
7314 </tr>
7315 <tr>
7316 <td>
7317 <p>
7318 NAPTR
7319 </p>
7320 </td>
7321 <td>
7322 <p>
7323 Name authority pointer. Described in RFC 2915.
7324 </p>
7325 </td>
7326 </tr>
7327 <tr>
7328 <td>
7329 <p>
7330 NSAP
7331 </p>
7332 </td>
7333 <td>
7334 <p>
7335 A network service access point.
7336 Described in RFC 1706.
7337 </p>
7338 </td>
7339 </tr>
7340 <tr>
7341 <td>
7342 <p>
7343 NS
7344 </p>
7345 </td>
7346 <td>
7347 <p>
7348 The authoritative name server for the
7349 domain. Described in RFC 1035.
7350 </p>
7351 </td>
7352 </tr>
7353 <tr>
7354 <td>
7355 <p>
7356 NSEC
7357 </p>
7358 </td>
7359 <td>
7360 <p>
7361 Used in DNSSECbis to securely indicate that
7362 RRs with an owner name in a certain name interval do
7363 not exist in
7364 a zone and indicate what RR types are present for an
7365 existing name.
7366 Described in RFC 4034.
7367 </p>
7368 </td>
7369 </tr>
7370 <tr>
7371 <td>
7372 <p>
7373 NSEC3
7374 </p>
7375 </td>
7376 <td>
7377 <p>
7378 Used in DNSSECbis to securely indicate that
7379 RRs with an owner name in a certain name
7380 interval do not exist in a zone and indicate
7381 what RR types are present for an existing
7382 name. NSEC3 differs from NSEC in that it
7383 prevents zone enumeration but is more
7384 computationally expensive on both the server
7385 and the client than NSEC. Described in RFC
7386 5155.
7387 </p>
7388 </td>
7389 </tr>
7390 <tr>
7391 <td>
7392 <p>
7393 NSEC3PARAM
7394 </p>
7395 </td>
7396 <td>
7397 <p>
7398 Used in DNSSECbis to tell the authoritative
7399 server which NSEC3 chains are available to use.
7400 Described in RFC 5155.
7401 </p>
7402 </td>
7403 </tr>
7404 <tr>
7405 <td>
7406 <p>
7407 NXT
7408 </p>
7409 </td>
7410 <td>
7411 <p>
7412 Used in DNSSEC to securely indicate that
7413 RRs with an owner name in a certain name interval do
7414 not exist in
7415 a zone and indicate what RR types are present for an
7416 existing name.
7417 Used in original DNSSEC; replaced by NSEC in
7418 DNSSECbis.
7419 Described in RFC 2535.
7420 </p>
7421 </td>
7422 </tr>
7423 <tr>
7424 <td>
7425 <p>
7426 PTR
7427 </p>
7428 </td>
7429 <td>
7430 <p>
7431 A pointer to another part of the domain
7432 name space. Described in RFC 1035.
7433 </p>
7434 </td>
7435 </tr>
7436 <tr>
7437 <td>
7438 <p>
7439 PX
7440 </p>
7441 </td>
7442 <td>
7443 <p>
7445 addresses. Described in RFC 2163.
7446 </p>
7447 </td>
7448 </tr>
7449 <tr>
7450 <td>
7451 <p>
7452 RP
7453 </p>
7454 </td>
7455 <td>
7456 <p>
7457 Information on persons responsible
7458 for the domain. Experimental. Described in RFC 1183.
7459 </p>
7460 </td>
7461 </tr>
7462 <tr>
7463 <td>
7464 <p>
7465 RRSIG
7466 </p>
7467 </td>
7468 <td>
7469 <p>
7470 Contains DNSSECbis signature data. Described
7471 in RFC 4034.
7472 </p>
7473 </td>
7474 </tr>
7475 <tr>
7476 <td>
7477 <p>
7478 RT
7479 </p>
7480 </td>
7481 <td>
7482 <p>
7483 Route-through binding for hosts that
7484 do not have their own direct wide area network
7485 addresses.
7486 Experimental. Described in RFC 1183.
7487 </p>
7488 </td>
7489 </tr>
7490 <tr>
7491 <td>
7492 <p>
7493 SIG
7494 </p>
7495 </td>
7496 <td>
7497 <p>
7498 Contains DNSSEC signature data. Used in
7499 original DNSSEC; replaced by RRSIG in
7500 DNSSECbis, but still used for SIG(0).
7502 </p>
7503 </td>
7504 </tr>
7505 <tr>
7506 <td>
7507 <p>
7508 SOA
7509 </p>
7510 </td>
7511 <td>
7512 <p>
7513 Identifies the start of a zone of authority.
7514 Described in RFC 1035.
7515 </p>
7516 </td>
7517 </tr>
7518 <tr>
7519 <td>
7520 <p>
7521 SPF
7522 </p>
7523 </td>
7524 <td>
7525 <p>
7526 Contains the Sender Policy Framework information
7527 for a given email domain. Described in RFC 4408.
7528 </p>
7529 </td>
7530 </tr>
7531 <tr>
7532 <td>
7533 <p>
7534 SRV
7535 </p>
7536 </td>
7537 <td>
7538 <p>
7539 Information about well known network
7540 services (replaces WKS). Described in RFC 2782.
7541 </p>
7542 </td>
7543 </tr>
7544 <tr>
7545 <td>
7546 <p>
7547 SSHFP
7548 </p>
7549 </td>
7550 <td>
7551 <p>
7552 Provides a way to securely publish a secure shell key's
7553 fingerprint. Described in RFC 4255.
7554 </p>
7555 </td>
7556 </tr>
7557 <tr>
7558 <td>
7559 <p>
7560 TXT
7561 </p>
7562 </td>
7563 <td>
7564 <p>
7565 Text records. Described in RFC 1035.
7566 </p>
7567 </td>
7568 </tr>
7569 <tr>
7570 <td>
7571 <p>
7572 WKS
7573 </p>
7574 </td>
7575 <td>
7576 <p>
7577 Information about which well known
7578 network services, such as SMTP, that a domain
7579 supports. Historical.
7580 </p>
7581 </td>
7582 </tr>
7583 <tr>
7584 <td>
7585 <p>
7586 X25
7587 </p>
7588 </td>
7589 <td>
7590 <p>
7591 Representation of X.25 network addresses.
7592 Experimental. Described in RFC 1183.
7593 </p>
7594 </td>
7595 </tr>
7596 </tbody>
7597 </table></div>
7598 <p>
7600 are currently valid in the DNS:
7601 </p>
7603 <colgroup>
7604 <col>
7605 <col>
7606 </colgroup>
7607 <tbody>
7608 <tr>
7609 <td>
7610 <p>
7611 IN
7612 </p>
7613 </td>
7614 <td>
7615 <p>
7616 The Internet.
7617 </p>
7618 </td>
7619 </tr>
7620 <tr>
7621 <td>
7622 <p>
7623 CH
7624 </p>
7625 </td>
7626 <td>
7627 <p>
7628 Chaosnet, a LAN protocol created at MIT in the
7629 mid-1970s.
7630 Rarely used for its historical purpose, but reused for
7631 BIND's
7632 built-in server information zones, e.g.,
7634 </p>
7635 </td>
7636 </tr>
7637 <tr>
7638 <td>
7639 <p>
7640 HS
7641 </p>
7642 </td>
7643 <td>
7644 <p>
7645 Hesiod, an information service
7646 developed by MIT's Project Athena. It is used to share
7647 information
7648 about various systems databases, such as users,
7649 groups, printers
7650 and so on.
7651 </p>
7652 </td>
7653 </tr>
7654 </tbody>
7655 </table></div>
7656 <p>
7657 The owner name is often implicit, rather than forming an
7658 integral
7659 part of the RR. For example, many name servers internally form
7660 tree
7661 or hash structures for the name space, and chain RRs off nodes.
7662 The remaining RR parts are the fixed header (type, class, TTL)
7663 which is consistent for all RRs, and a variable part (RDATA)
7664 that
7665 fits the needs of the resource being described.
7666 </p>
7667 <p>
7668 The meaning of the TTL field is a time limit on how long an
7669 RR can be kept in a cache. This limit does not apply to
7670 authoritative
7671 data in zones; it is also timed out, but by the refreshing
7672 policies
7673 for the zone. The TTL is assigned by the administrator for the
7674 zone where the data originates. While short TTLs can be used to
7675 minimize caching, and a zero TTL prohibits caching, the
7676 realities
7677 of Internet performance suggest that these times should be on
7678 the
7679 order of days for the typical host. If a change can be
7680 anticipated,
7681 the TTL can be reduced prior to the change to minimize
7682 inconsistency
7683 during the change, and then increased back to its former value
7684 following
7685 the change.
7686 </p>
7687 <p>
7688 The data in the RDATA section of RRs is carried as a combination
7689 of binary strings and domain names. The domain names are
7690 frequently
7691 used as "pointers" to other data in the DNS.
7692 </p>
7693 </div>
7697 <p>
7698 RRs are represented in binary form in the packets of the DNS
7699 protocol, and are usually represented in highly encoded form
7700 when
7701 stored in a name server or resolver. In the examples provided
7702 in
7703 RFC 1034, a style similar to that used in master files was
7704 employed
7705 in order to show the contents of RRs. In this format, most RRs
7706 are shown on a single line, although continuation lines are
7707 possible
7708 using parentheses.
7709 </p>
7710 <p>
7711 The start of the line gives the owner of the RR. If a line
7712 begins with a blank, then the owner is assumed to be the same as
7713 that of the previous RR. Blank lines are often included for
7714 readability.
7715 </p>
7716 <p>
7717 Following the owner, we list the TTL, type, and class of the
7718 RR. Class and type use the mnemonics defined above, and TTL is
7719 an integer before the type field. In order to avoid ambiguity
7720 in
7721 parsing, type and class mnemonics are disjoint, TTLs are
7722 integers,
7723 and the type mnemonic is always last. The IN class and TTL
7724 values
7725 are often omitted from examples in the interests of clarity.
7726 </p>
7727 <p>
7728 The resource data or RDATA section of the RR are given using
7729 knowledge of the typical representation for the data.
7730 </p>
7731 <p>
7732 For example, we might show the RRs carried in a message as:
7733 </p>
7735 <colgroup>
7736 <col>
7737 <col>
7738 <col>
7739 </colgroup>
7740 <tbody>
7741 <tr>
7742 <td>
7743 <p>
7745 </p>
7746 </td>
7747 <td>
7748 <p>
7750 </p>
7751 </td>
7752 <td>
7753 <p>
7755 </p>
7756 </td>
7757 </tr>
7758 <tr>
7759 <td>
7760 <p></p>
7761 </td>
7762 <td>
7763 <p>
7765 </p>
7766 </td>
7767 <td>
7768 <p>
7770 </p>
7771 </td>
7772 </tr>
7773 <tr>
7774 <td>
7775 <p>
7777 </p>
7778 </td>
7779 <td>
7780 <p>
7782 </p>
7783 </td>
7784 <td>
7785 <p>
7787 </p>
7788 </td>
7789 </tr>
7790 <tr>
7791 <td>
7792 <p></p>
7793 </td>
7794 <td>
7795 <p>
7797 </p>
7798 </td>
7799 <td>
7800 <p>
7802 </p>
7803 </td>
7804 </tr>
7805 <tr>
7806 <td>
7807 <p>
7809 </p>
7810 </td>
7811 <td>
7812 <p>
7814 </p>
7815 </td>
7816 <td>
7817 <p>
7819 </p>
7820 </td>
7821 </tr>
7822 <tr>
7823 <td>
7824 <p></p>
7825 </td>
7826 <td>
7827 <p>
7829 </p>
7830 </td>
7831 <td>
7832 <p>
7834 </p>
7835 </td>
7836 </tr>
7837 </tbody>
7838 </table></div>
7839 <p>
7840 The MX RRs have an RDATA section which consists of a 16-bit
7841 number followed by a domain name. The address RRs use a
7842 standard
7843 IP address format to contain a 32-bit internet address.
7844 </p>
7845 <p>
7846 The above example shows six RRs, with two RRs at each of three
7847 domain names.
7848 </p>
7849 <p>
7850 Similarly we might see:
7851 </p>
7853 <colgroup>
7854 <col>
7855 <col>
7856 <col>
7857 </colgroup>
7858 <tbody>
7859 <tr>
7860 <td>
7861 <p>
7863 </p>
7864 </td>
7865 <td>
7866 <p>
7868 </p>
7869 </td>
7870 <td>
7871 <p>
7873 </p>
7874 </td>
7875 </tr>
7876 <tr>
7878 <td>
7879 <p>
7881 </p>
7882 </td>
7883 <td>
7884 <p>
7886 </p>
7887 </td>
7888 </tr>
7889 </tbody>
7890 </table></div>
7891 <p>
7892 This example shows two addresses for
7894 </p>
7895 </div>
7896 </div>
7900 <p>
7901 As described above, domain servers store information as a
7902 series of resource records, each of which contains a particular
7903 piece of information about a given domain name (which is usually,
7904 but not always, a host). The simplest way to think of a RR is as
7905 a typed pair of data, a domain name matched with a relevant datum,
7906 and stored with some additional type information to help systems
7907 determine when the RR is relevant.
7908 </p>
7909 <p>
7910 MX records are used to control delivery of email. The data
7911 specified in the record is a priority and a domain name. The
7912 priority
7913 controls the order in which email delivery is attempted, with the
7914 lowest number first. If two priorities are the same, a server is
7915 chosen randomly. If no servers at a given priority are responding,
7916 the mail transport agent will fall back to the next largest
7917 priority.
7918 Priority numbers do not have any absolute meaning — they are
7919 relevant
7920 only respective to other MX records for that domain name. The
7921 domain
7922 name given is the machine to which the mail will be delivered.
7924 (A or AAAA) — CNAME is not sufficient.
7925 </p>
7926 <p>
7927 For a given domain, if there is both a CNAME record and an
7928 MX record, the MX record is in error, and will be ignored.
7929 Instead,
7930 the mail will be delivered to the server specified in the MX
7931 record
7932 pointed to by the CNAME.
7933 For example:
7934 </p>
7936 <colgroup>
7937 <col>
7938 <col>
7939 <col>
7940 <col>
7941 <col>
7942 </colgroup>
7943 <tbody>
7944 <tr>
7945 <td>
7946 <p>
7948 </p>
7949 </td>
7950 <td>
7951 <p>
7953 </p>
7954 </td>
7955 <td>
7956 <p>
7958 </p>
7959 </td>
7960 <td>
7961 <p>
7963 </p>
7964 </td>
7965 <td>
7966 <p>
7968 </p>
7969 </td>
7970 </tr>
7971 <tr>
7972 <td>
7973 <p></p>
7974 </td>
7975 <td>
7976 <p>
7978 </p>
7979 </td>
7980 <td>
7981 <p>
7983 </p>
7984 </td>
7985 <td>
7986 <p>
7988 </p>
7989 </td>
7990 <td>
7991 <p>
7993 </p>
7994 </td>
7995 </tr>
7996 <tr>
7997 <td>
7998 <p></p>
7999 </td>
8000 <td>
8001 <p>
8003 </p>
8004 </td>
8005 <td>
8006 <p>
8008 </p>
8009 </td>
8010 <td>
8011 <p>
8013 </p>
8014 </td>
8015 <td>
8016 <p>
8018 </p>
8019 </td>
8020 </tr>
8021 <tr>
8022 <td>
8023 <p>
8025 </p>
8026 </td>
8027 <td>
8028 <p>
8030 </p>
8031 </td>
8032 <td>
8033 <p>
8035 </p>
8036 </td>
8037 <td>
8038 <p>
8040 </p>
8041 </td>
8042 <td>
8043 <p></p>
8044 </td>
8045 </tr>
8046 <tr>
8047 <td>
8048 <p>
8050 </p>
8051 </td>
8052 <td>
8053 <p>
8055 </p>
8056 </td>
8057 <td>
8058 <p>
8060 </p>
8061 </td>
8062 <td>
8063 <p>
8065 </p>
8066 </td>
8067 <td>
8068 <p></p>
8069 </td>
8070 </tr>
8071 </tbody>
8072 </table></div>
8073 <p>
8076 any order), and if neither of those succeed, delivery to <code class="literal">mail.backup.org</code> will
8077 be attempted.
8078 </p>
8079 </div>
8083 <p>
8084 The time-to-live of the RR field is a 32-bit integer represented
8085 in units of seconds, and is primarily used by resolvers when they
8086 cache RRs. The TTL describes how long a RR can be cached before it
8087 should be discarded. The following three types of TTL are
8088 currently
8089 used in a zone file.
8090 </p>
8092 <colgroup>
8093 <col>
8094 <col>
8095 </colgroup>
8096 <tbody>
8097 <tr>
8098 <td>
8099 <p>
8100 SOA
8101 </p>
8102 </td>
8103 <td>
8104 <p>
8105 The last field in the SOA is the negative
8106 caching TTL. This controls how long other servers will
8107 cache no-such-domain
8108 (NXDOMAIN) responses from you.
8109 </p>
8110 <p>
8111 The maximum time for
8113 </p>
8114 </td>
8115 </tr>
8116 <tr>
8117 <td>
8118 <p>
8119 $TTL
8120 </p>
8121 </td>
8122 <td>
8123 <p>
8124 The $TTL directive at the top of the
8125 zone file (before the SOA) gives a default TTL for every
8126 RR without
8127 a specific TTL set.
8128 </p>
8129 </td>
8130 </tr>
8131 <tr>
8132 <td>
8133 <p>
8134 RR TTLs
8135 </p>
8136 </td>
8137 <td>
8138 <p>
8139 Each RR can have a TTL as the second
8140 field in the RR, which will control how long other
8141 servers can cache
8142 the it.
8143 </p>
8144 </td>
8145 </tr>
8146 </tbody>
8147 </table></div>
8148 <p>
8149 All of these TTLs default to units of seconds, though units
8151 </p>
8152 </div>
8156 <p>
8157 Reverse name resolution (that is, translation from IP address
8158 to name) is achieved by means of the <span class="emphasis"><em>in-addr.arpa</em></span> domain
8159 and PTR records. Entries in the in-addr.arpa domain are made in
8160 least-to-most significant order, read left to right. This is the
8161 opposite order to the way IP addresses are usually written. Thus,
8162 a machine with an IP address of 10.1.2.3 would have a
8163 corresponding
8164 in-addr.arpa name of
8165 3.2.1.10.in-addr.arpa. This name should have a PTR resource record
8166 whose data field is the name of the machine or, optionally,
8167 multiple
8168 PTR records if the machine has more than one name. For example,
8170 </p>
8172 <colgroup>
8173 <col>
8174 <col>
8175 </colgroup>
8176 <tbody>
8177 <tr>
8178 <td>
8179 <p>
8181 </p>
8182 </td>
8183 <td>
8184 <p>
8186 </p>
8187 </td>
8188 </tr>
8189 <tr>
8190 <td>
8191 <p>
8193 </p>
8194 </td>
8195 <td>
8196 <p>
8198 </p>
8199 </td>
8200 </tr>
8201 </tbody>
8202 </table></div>
8205 <p>
8207 are for providing context to the examples only — they do not
8208 necessarily
8209 appear in the actual usage. They are only used here to indicate
8210 that the example is relative to the listed origin.
8211 </p>
8212 </div>
8213 </div>
8217 <p>
8218 The Master File Format was initially defined in RFC 1035 and
8219 has subsequently been extended. While the Master File Format
8220 itself
8221 is class independent all records in a Master File must be of the
8222 same
8223 class.
8224 </p>
8225 <p>
8226 Master File Directives include <span><strong class="command">$ORIGIN</strong></span>, <span><strong class="command">$INCLUDE</strong></span>,
8228 </p>
8231 <a name="id2596152"></a>The <span><strong class="command">@</strong></span> (at-sign)</h4></div></div></div>
8232 <p>
8233 When used in the label (or name) field, the asperand or
8234 at-sign (@) symbol represents the current origin.
8235 At the start of the zone file, it is the
8237 trailing dot).
8238 </p>
8239 </div>
8242 <a name="id2596168"></a>The <span><strong class="command">$ORIGIN</strong></span> Directive</h4></div></div></div>
8243 <p>
8247 </p>
8249 sets the domain name that will be appended to any
8250 unqualified records. When a zone is first read in there
8253 (followed by trailing dot).
8256 argument if it is not absolute.
8257 </p>
8259 $ORIGIN example.com.
8260 WWW CNAME MAIN-SERVER
8261 </pre>
8262 <p>
8263 is equivalent to
8264 </p>
8266 WWW.EXAMPLE.COM. CNAME MAIN-SERVER.EXAMPLE.COM.
8267 </pre>
8268 </div>
8271 <a name="id2596229"></a>The <span><strong class="command">$INCLUDE</strong></span> Directive</h4></div></div></div>
8272 <p>
8278 </p>
8279 <p>
8281 if it were included into the file at this point. If <span><strong class="command">origin</strong></span> is
8284 used.
8285 </p>
8286 <p>
8287 The origin and the current domain name
8288 revert to the values they had prior to the <span><strong class="command">$INCLUDE</strong></span> once
8289 the file has been read.
8290 </p>
8293 <p>
8294 RFC 1035 specifies that the current origin should be restored
8295 after
8297 on whether the current
8298 domain name should also be restored. BIND 9 restores both of
8299 them.
8300 This could be construed as a deviation from RFC 1035, a
8301 feature, or both.
8302 </p>
8303 </div>
8304 </div>
8307 <a name="id2596298"></a>The <span><strong class="command">$TTL</strong></span> Directive</h4></div></div></div>
8308 <p>
8313 </p>
8314 <p>
8315 Set the default Time To Live (TTL) for subsequent records
8317 seconds.
8318 </p>
8320 is defined in RFC 2308.
8321 </p>
8322 </div>
8323 </div>
8326 <a name="id2596403"></a><acronym class="acronym">BIND</acronym> Master File Extension: the <span><strong class="command">$GENERATE</strong></span> Directive</h3></div></div></div>
8327 <p>
8336 </p>
8338 is used to create a series of resource records that only
8339 differ from each other by an
8341 easily generate the sets of records required to support
8343 Classless IN-ADDR.ARPA delegation.
8344 </p>
8348 <p>
8349 is equivalent to
8350 </p>
8352 0.0.0.192.IN-ADDR.ARPA. NS SERVER2.EXAMPLE.
8355 ...
8357 </pre>
8358 <p>
8359 Generate a set of A and MX records. Note the MX's right hand
8360 side is a quoted string. The quotes will be stripped when the
8361 right hand side is processed.
8362 </p>
8364 $ORIGIN EXAMPLE.
8367 <p>
8368 is equivalent to
8369 </p>
8376 ...
8379 </pre>
8381 <colgroup>
8382 <col>
8383 <col>
8384 </colgroup>
8385 <tbody>
8386 <tr>
8387 <td>
8389 </td>
8390 <td>
8391 <p>
8392 This can be one of two forms: start-stop
8393 or start-stop/step. If the first form is used, then step
8394 is set to
8395 1. All of start, stop and step must be positive.
8396 </p>
8397 </td>
8398 </tr>
8399 <tr>
8400 <td>
8402 </td>
8403 <td>
8404 <p>This
8405 describes the owner name of the resource records
8407 (dollar sign)
8409 are replaced by the iterator value.
8411 To get a $ in the output, you need to escape the
8416 by modifiers which change the offset from the
8417 iterator, field width and base.
8419 Modifiers are introduced by a
8424 subtracts 20 from the current value, prints the
8425 result as a decimal in a zero-padded field of
8426 width 3.
8428 Available output forms are decimal
8431 (<span><strong class="command">x</strong></span> or <span><strong class="command">X</strong></span>
8432 for uppercase) and nibble
8433 (<span><strong class="command">n</strong></span> or <span><strong class="command">N</strong></span>\
8434 for uppercase). The default modifier is
8438 to the name.
8439 </p>
8440 <p>
8441 In nibble mode the value will be treated as
8442 if it was a reversed hexadecimal string
8443 with each hexadecimal digit as a separate
8444 label. The width field includes the label
8445 separator.
8446 </p>
8447 <p>
8448 For compatibility with earlier versions,
8450 indicating a literal $ in the output.
8451 </p>
8452 </td>
8453 </tr>
8454 <tr>
8455 <td>
8457 </td>
8458 <td>
8459 <p>
8460 Specifies the time-to-live of the generated records. If
8461 not specified this will be inherited using the
8462 normal TTL inheritance rules.
8463 </p>
8466 entered in either order.
8467 </p>
8468 </td>
8469 </tr>
8470 <tr>
8471 <td>
8473 </td>
8474 <td>
8475 <p>
8476 Specifies the class of the generated records.
8477 This must match the zone class if it is
8478 specified.
8479 </p>
8482 entered in either order.
8483 </p>
8484 </td>
8485 </tr>
8486 <tr>
8487 <td>
8489 </td>
8490 <td>
8491 <p>
8492 Any valid type.
8493 </p>
8494 </td>
8495 </tr>
8496 <tr>
8497 <td>
8499 </td>
8500 <td>
8501 <p>
8503 </p>
8504 </td>
8505 </tr>
8506 </tbody>
8507 </table></div>
8508 <p>
8509 The <span><strong class="command">$GENERATE</strong></span> directive is a <acronym class="acronym">BIND</acronym> extension
8510 and not part of the standard zone file format.
8511 </p>
8512 <p>
8513 BIND 8 does not support the optional TTL and CLASS fields.
8514 </p>
8515 </div>
8519 <p>
8520 In addition to the standard textual format, BIND 9
8521 supports the ability to read or dump to zone files in
8523 currently available as an additional format. It is a
8524 binary format representing BIND 9's internal data
8525 structure directly, thereby remarkably improving the
8526 loading time.
8527 </p>
8528 <p>
8529 For a primary server, a zone file in the
8531 generated from a textual zone file by the
8533 secondary server or for a dynamic zone, it is automatically
8534 generated (if this format is specified by the
8537 zone transfer or when applying prior updates.
8538 </p>
8539 <p>
8540 If a zone file in a binary format needs manual modification,
8541 it first must be converted to a textual form by the
8543 necessary modification should go to the text file, which
8544 should then be converted to the binary form by the
8546 </p>
8547 <p>
8549 network byte order and avoids architecture-dependent
8550 data alignment so that it is as much portable as
8551 possible, it is primarily expected to be used inside
8552 the same single system. In order to export a zone
8554 portable backup of the file, it is recommended to
8555 convert the file to the standard textual representation.
8556 </p>
8557 </div>
8558 </div>
8562 <p>
8564 information and provides several interfaces for users to
8565 get access to the statistics.
8566 The available statistics include all statistics counters
8569 and other information that is considered useful.
8570 </p>
8571 <p>
8572 The statistics information is categorized into the following
8573 sections.
8574 </p>
8576 <colgroup>
8577 <col>
8578 <col>
8579 </colgroup>
8580 <tbody>
8581 <tr>
8582 <td>
8584 </td>
8585 <td>
8586 <p>
8587 The number of incoming DNS requests for each OPCODE.
8588 </p>
8589 </td>
8590 </tr>
8591 <tr>
8592 <td>
8594 </td>
8595 <td>
8596 <p>
8597 The number of incoming queries for each RR type.
8598 </p>
8599 </td>
8600 </tr>
8601 <tr>
8602 <td>
8604 </td>
8605 <td>
8606 <p>
8607 The number of outgoing queries for each RR
8608 type sent from the internal resolver.
8609 Maintained per view.
8610 </p>
8611 </td>
8612 </tr>
8613 <tr>
8614 <td>
8616 </td>
8617 <td>
8618 <p>
8619 Statistics counters about incoming request processing.
8620 </p>
8621 </td>
8622 </tr>
8623 <tr>
8624 <td>
8626 </td>
8627 <td>
8628 <p>
8629 Statistics counters regarding zone maintenance
8630 operations such as zone transfers.
8631 </p>
8632 </td>
8633 </tr>
8634 <tr>
8635 <td>
8637 </td>
8638 <td>
8639 <p>
8640 Statistics counters about name resolution
8641 performed in the internal resolver.
8642 Maintained per view.
8643 </p>
8644 </td>
8645 </tr>
8646 <tr>
8647 <td>
8649 </td>
8650 <td>
8651 <p>
8652 The number of RRsets per RR type and nonexistent
8653 names stored in the cache database.
8654 If the exclamation mark (!) is printed for a RR
8655 type, it means that particular type of RRset is
8656 known to be nonexistent (this is also known as
8657 "NXRRSET").
8658 Maintained per view.
8659 </p>
8660 </td>
8661 </tr>
8662 <tr>
8663 <td>
8665 </td>
8666 <td>
8667 <p>
8668 Statistics counters about network related events.
8669 </p>
8670 </td>
8671 </tr>
8672 </tbody>
8673 </table></div>
8674 <p>
8675 A subset of Name Server Statistics is collected and shown
8676 per zone for which the server has the authority when
8679 These statistics counters are shown with their zone and view
8680 names.
8681 In some cases the view names are omitted for the default view.
8682 </p>
8683 <p>
8684 There are currently two user interfaces to get access to the
8685 statistics.
8686 One is in the plain text format dumped to the file specified
8688 The other is remotely accessible via a statistics channel
8690 is specified in the configuration file
8691 (see <a href="Bv9ARM.ch06.html#statschannels" title="statistics-channels Statement Grammar">the section called “<span><strong class="command">statistics-channels</strong></span> Statement Grammar”</a>.)
8692 </p>
8696 <p>
8697 The text format statistics dump begins with a line, like:
8698 </p>
8699 <p>
8701 </p>
8702 <p>
8703 The number in parentheses is a standard
8706 Following
8707 that line is a set of statistics information, which is categorized
8708 as described above.
8709 Each section begins with a line, like:
8710 </p>
8711 <p>
8713 </p>
8714 <p>
8715 Each section consists of lines, each containing the statistics
8716 counter value followed by its textual description.
8717 See below for available counters.
8718 For brevity, counters that have a value of 0 are not shown
8719 in the statistics file.
8720 </p>
8721 <p>
8722 The statistics dump ends with the line where the
8723 number is identical to the number in the beginning line; for example:
8724 </p>
8725 <p>
8727 </p>
8728 </div>
8732 <p>
8733 The following tables summarize statistics counters that
8735 For each row of the tables, the leftmost column is the
8736 abbreviated symbol name of that counter.
8737 These symbols are shown in the statistics information
8738 accessed via an HTTP statistics channel.
8739 The rightmost column gives the description of the counter,
8740 which is also shown in the statistics file
8741 (but, in this document, possibly with slight modification
8742 for better readability).
8743 Additional notes may also be provided in this column.
8744 When a middle column exists between these two columns,
8745 it gives the corresponding counter name of the
8747 </p>
8752 <colgroup>
8753 <col>
8754 <col>
8755 <col>
8756 </colgroup>
8757 <tbody>
8758 <tr>
8759 <td>
8760 <p>
8762 </p>
8763 </td>
8764 <td>
8765 <p>
8767 </p>
8768 </td>
8769 <td>
8770 <p>
8772 </p>
8773 </td>
8774 </tr>
8775 <tr>
8776 <td>
8778 </td>
8779 <td>
8781 </td>
8782 <td>
8783 <p>
8784 IPv4 requests received.
8785 Note: this also counts non query requests.
8786 </p>
8787 </td>
8788 </tr>
8789 <tr>
8790 <td>
8792 </td>
8793 <td>
8795 </td>
8796 <td>
8797 <p>
8798 IPv6 requests received.
8799 Note: this also counts non query requests.
8800 </p>
8801 </td>
8802 </tr>
8803 <tr>
8804 <td>
8806 </td>
8807 <td>
8809 </td>
8810 <td>
8811 <p>
8812 Requests with EDNS(0) received.
8813 </p>
8814 </td>
8815 </tr>
8816 <tr>
8817 <td>
8819 </td>
8820 <td>
8822 </td>
8823 <td>
8824 <p>
8825 Requests with unsupported EDNS version received.
8826 </p>
8827 </td>
8828 </tr>
8829 <tr>
8830 <td>
8832 </td>
8833 <td>
8835 </td>
8836 <td>
8837 <p>
8838 Requests with TSIG received.
8839 </p>
8840 </td>
8841 </tr>
8842 <tr>
8843 <td>
8845 </td>
8846 <td>
8848 </td>
8849 <td>
8850 <p>
8851 Requests with SIG(0) received.
8852 </p>
8853 </td>
8854 </tr>
8855 <tr>
8856 <td>
8858 </td>
8859 <td>
8861 </td>
8862 <td>
8863 <p>
8864 Requests with invalid (TSIG or SIG(0)) signature.
8865 </p>
8866 </td>
8867 </tr>
8868 <tr>
8869 <td>
8871 </td>
8872 <td>
8874 </td>
8875 <td>
8876 <p>
8877 TCP requests received.
8878 </p>
8879 </td>
8880 </tr>
8881 <tr>
8882 <td>
8884 </td>
8885 <td>
8887 </td>
8888 <td>
8889 <p>
8890 Authoritative (non recursive) queries rejected.
8891 </p>
8892 </td>
8893 </tr>
8894 <tr>
8895 <td>
8897 </td>
8898 <td>
8900 </td>
8901 <td>
8902 <p>
8903 Recursive queries rejected.
8904 </p>
8905 </td>
8906 </tr>
8907 <tr>
8908 <td>
8910 </td>
8911 <td>
8913 </td>
8914 <td>
8915 <p>
8916 Zone transfer requests rejected.
8917 </p>
8918 </td>
8919 </tr>
8920 <tr>
8921 <td>
8923 </td>
8924 <td>
8926 </td>
8927 <td>
8928 <p>
8929 Dynamic update requests rejected.
8930 </p>
8931 </td>
8932 </tr>
8933 <tr>
8934 <td>
8936 </td>
8937 <td>
8939 </td>
8940 <td>
8941 <p>
8942 Responses sent.
8943 </p>
8944 </td>
8945 </tr>
8946 <tr>
8947 <td>
8949 </td>
8950 <td>
8952 </td>
8953 <td>
8954 <p>
8955 Truncated responses sent.
8956 </p>
8957 </td>
8958 </tr>
8959 <tr>
8960 <td>
8962 </td>
8963 <td>
8965 </td>
8966 <td>
8967 <p>
8968 Responses with EDNS(0) sent.
8969 </p>
8970 </td>
8971 </tr>
8972 <tr>
8973 <td>
8975 </td>
8976 <td>
8978 </td>
8979 <td>
8980 <p>
8981 Responses with TSIG sent.
8982 </p>
8983 </td>
8984 </tr>
8985 <tr>
8986 <td>
8988 </td>
8989 <td>
8991 </td>
8992 <td>
8993 <p>
8994 Responses with SIG(0) sent.
8995 </p>
8996 </td>
8997 </tr>
8998 <tr>
8999 <td>
9001 </td>
9002 <td>
9004 </td>
9005 <td>
9006 <p>
9007 Queries resulted in a successful answer.
9008 This means the query which returns a NOERROR response
9009 with at least one answer RR.
9010 This corresponds to the
9012 of previous versions of
9014 </p>
9015 </td>
9016 </tr>
9017 <tr>
9018 <td>
9020 </td>
9021 <td>
9023 </td>
9024 <td>
9025 <p>
9026 Queries resulted in authoritative answer.
9027 </p>
9028 </td>
9029 </tr>
9030 <tr>
9031 <td>
9033 </td>
9034 <td>
9036 </td>
9037 <td>
9038 <p>
9039 Queries resulted in non authoritative answer.
9040 </p>
9041 </td>
9042 </tr>
9043 <tr>
9044 <td>
9046 </td>
9047 <td>
9049 </td>
9050 <td>
9051 <p>
9052 Queries resulted in referral answer.
9053 This corresponds to the
9055 of previous versions of
9057 </p>
9058 </td>
9059 </tr>
9060 <tr>
9061 <td>
9063 </td>
9064 <td>
9066 </td>
9067 <td>
9068 <p>
9069 Queries resulted in NOERROR responses with no data.
9070 This corresponds to the
9072 of previous versions of
9074 </p>
9075 </td>
9076 </tr>
9077 <tr>
9078 <td>
9080 </td>
9081 <td>
9083 </td>
9084 <td>
9085 <p>
9086 Queries resulted in SERVFAIL.
9087 </p>
9088 </td>
9089 </tr>
9090 <tr>
9091 <td>
9093 </td>
9094 <td>
9096 </td>
9097 <td>
9098 <p>
9099 Queries resulted in FORMERR.
9100 </p>
9101 </td>
9102 </tr>
9103 <tr>
9104 <td>
9106 </td>
9107 <td>
9109 </td>
9110 <td>
9111 <p>
9112 Queries resulted in NXDOMAIN.
9113 This corresponds to the
9115 of previous versions of
9117 </p>
9118 </td>
9119 </tr>
9120 <tr>
9121 <td>
9123 </td>
9124 <td>
9126 </td>
9127 <td>
9128 <p>
9129 Queries which caused the server
9130 to perform recursion in order to find the final answer.
9131 This corresponds to the
9133 of previous versions of
9135 </p>
9136 </td>
9137 </tr>
9138 <tr>
9139 <td>
9141 </td>
9142 <td>
9144 </td>
9145 <td>
9146 <p>
9147 Queries which the server attempted to
9148 recurse but discovered an existing query with the same
9149 IP address, port, query ID, name, type and class
9150 already being processed.
9151 This corresponds to the
9153 of previous versions of
9155 </p>
9156 </td>
9157 </tr>
9158 <tr>
9159 <td>
9161 </td>
9162 <td>
9164 </td>
9165 <td>
9166 <p>
9167 Recursive queries for which the server
9168 discovered an excessive number of existing
9169 recursive queries for the same name, type and
9170 class and were subsequently dropped.
9171 This is the number of dropped queries due to
9172 the reason explained with the
9174 and
9176 options
9177 (see the description about
9178 <a href="Bv9ARM.ch06.html#clients-per-query"><span><strong class="command">clients-per-query</strong></span></a>.)
9179 This corresponds to the
9181 of previous versions of
9183 </p>
9184 </td>
9185 </tr>
9186 <tr>
9187 <td>
9189 </td>
9190 <td>
9192 </td>
9193 <td>
9194 <p>
9195 Other query failures.
9196 This corresponds to the
9198 of previous versions of
9200 Note: this counter is provided mainly for
9201 backward compatibility with the previous versions.
9202 Normally a more fine-grained counters such as
9205 that would also fall into this counter are provided,
9206 and so this counter would not be of much
9207 interest in practice.
9208 </p>
9209 </td>
9210 </tr>
9211 <tr>
9212 <td>
9214 </td>
9215 <td>
9217 </td>
9218 <td>
9219 <p>
9220 Requested zone transfers completed.
9221 </p>
9222 </td>
9223 </tr>
9224 <tr>
9225 <td>
9227 </td>
9228 <td>
9230 </td>
9231 <td>
9232 <p>
9233 Update requests forwarded.
9234 </p>
9235 </td>
9236 </tr>
9237 <tr>
9238 <td>
9240 </td>
9241 <td>
9243 </td>
9244 <td>
9245 <p>
9246 Update responses forwarded.
9247 </p>
9248 </td>
9249 </tr>
9250 <tr>
9251 <td>
9253 </td>
9254 <td>
9256 </td>
9257 <td>
9258 <p>
9259 Dynamic update forward failed.
9260 </p>
9261 </td>
9262 </tr>
9263 <tr>
9264 <td>
9266 </td>
9267 <td>
9269 </td>
9270 <td>
9271 <p>
9272 Dynamic updates completed.
9273 </p>
9274 </td>
9275 </tr>
9276 <tr>
9277 <td>
9279 </td>
9280 <td>
9282 </td>
9283 <td>
9284 <p>
9285 Dynamic updates failed.
9286 </p>
9287 </td>
9288 </tr>
9289 <tr>
9290 <td>
9292 </td>
9293 <td>
9295 </td>
9296 <td>
9297 <p>
9298 Dynamic updates rejected due to prerequisite failure.
9299 </p>
9300 </td>
9301 </tr>
9302 </tbody>
9303 </table></div>
9304 </div>
9309 <colgroup>
9310 <col>
9311 <col>
9312 </colgroup>
9313 <tbody>
9314 <tr>
9315 <td>
9316 <p>
9318 </p>
9319 </td>
9320 <td>
9321 <p>
9323 </p>
9324 </td>
9325 </tr>
9326 <tr>
9327 <td>
9329 </td>
9330 <td>
9331 <p>
9332 IPv4 notifies sent.
9333 </p>
9334 </td>
9335 </tr>
9336 <tr>
9337 <td>
9339 </td>
9340 <td>
9341 <p>
9342 IPv6 notifies sent.
9343 </p>
9344 </td>
9345 </tr>
9346 <tr>
9347 <td>
9349 </td>
9350 <td>
9351 <p>
9352 IPv4 notifies received.
9353 </p>
9354 </td>
9355 </tr>
9356 <tr>
9357 <td>
9359 </td>
9360 <td>
9361 <p>
9362 IPv6 notifies received.
9363 </p>
9364 </td>
9365 </tr>
9366 <tr>
9367 <td>
9369 </td>
9370 <td>
9371 <p>
9372 Incoming notifies rejected.
9373 </p>
9374 </td>
9375 </tr>
9376 <tr>
9377 <td>
9379 </td>
9380 <td>
9381 <p>
9382 IPv4 SOA queries sent.
9383 </p>
9384 </td>
9385 </tr>
9386 <tr>
9387 <td>
9389 </td>
9390 <td>
9391 <p>
9392 IPv6 SOA queries sent.
9393 </p>
9394 </td>
9395 </tr>
9396 <tr>
9397 <td>
9399 </td>
9400 <td>
9401 <p>
9402 IPv4 AXFR requested.
9403 </p>
9404 </td>
9405 </tr>
9406 <tr>
9407 <td>
9409 </td>
9410 <td>
9411 <p>
9412 IPv6 AXFR requested.
9413 </p>
9414 </td>
9415 </tr>
9416 <tr>
9417 <td>
9419 </td>
9420 <td>
9421 <p>
9422 IPv4 IXFR requested.
9423 </p>
9424 </td>
9425 </tr>
9426 <tr>
9427 <td>
9429 </td>
9430 <td>
9431 <p>
9432 IPv6 IXFR requested.
9433 </p>
9434 </td>
9435 </tr>
9436 <tr>
9437 <td>
9439 </td>
9440 <td>
9441 <p>
9442 Zone transfer requests succeeded.
9443 </p>
9444 </td>
9445 </tr>
9446 <tr>
9447 <td>
9449 </td>
9450 <td>
9451 <p>
9452 Zone transfer requests failed.
9453 </p>
9454 </td>
9455 </tr>
9456 </tbody>
9457 </table></div>
9458 </div>
9463 <colgroup>
9464 <col>
9465 <col>
9466 <col>
9467 </colgroup>
9468 <tbody>
9469 <tr>
9470 <td>
9471 <p>
9473 </p>
9474 </td>
9475 <td>
9476 <p>
9478 </p>
9479 </td>
9480 <td>
9481 <p>
9483 </p>
9484 </td>
9485 </tr>
9486 <tr>
9487 <td>
9489 </td>
9490 <td>
9492 </td>
9493 <td>
9494 <p>
9495 IPv4 queries sent.
9496 </p>
9497 </td>
9498 </tr>
9499 <tr>
9500 <td>
9502 </td>
9503 <td>
9505 </td>
9506 <td>
9507 <p>
9508 IPv6 queries sent.
9509 </p>
9510 </td>
9511 </tr>
9512 <tr>
9513 <td>
9515 </td>
9516 <td>
9518 </td>
9519 <td>
9520 <p>
9521 IPv4 responses received.
9522 </p>
9523 </td>
9524 </tr>
9525 <tr>
9526 <td>
9528 </td>
9529 <td>
9531 </td>
9532 <td>
9533 <p>
9534 IPv6 responses received.
9535 </p>
9536 </td>
9537 </tr>
9538 <tr>
9539 <td>
9541 </td>
9542 <td>
9544 </td>
9545 <td>
9546 <p>
9547 NXDOMAIN received.
9548 </p>
9549 </td>
9550 </tr>
9551 <tr>
9552 <td>
9554 </td>
9555 <td>
9557 </td>
9558 <td>
9559 <p>
9560 SERVFAIL received.
9561 </p>
9562 </td>
9563 </tr>
9564 <tr>
9565 <td>
9567 </td>
9568 <td>
9570 </td>
9571 <td>
9572 <p>
9573 FORMERR received.
9574 </p>
9575 </td>
9576 </tr>
9577 <tr>
9578 <td>
9580 </td>
9581 <td>
9583 </td>
9584 <td>
9585 <p>
9586 Other errors received.
9587 </p>
9588 </td>
9589 </tr>
9590 <tr>
9591 <td>
9593 </td>
9594 <td>
9596 </td>
9597 <td>
9598 <p>
9599 EDNS(0) query failures.
9600 </p>
9601 </td>
9602 </tr>
9603 <tr>
9604 <td>
9606 </td>
9607 <td>
9609 </td>
9610 <td>
9611 <p>
9612 Mismatch responses received.
9613 The DNS ID, response's source address,
9614 and/or the response's source port does not
9615 match what was expected.
9616 (The port must be 53 or as defined by
9618 This may be an indication of a cache
9619 poisoning attempt.
9620 </p>
9621 </td>
9622 </tr>
9623 <tr>
9624 <td>
9626 </td>
9627 <td>
9629 </td>
9630 <td>
9631 <p>
9632 Truncated responses received.
9633 </p>
9634 </td>
9635 </tr>
9636 <tr>
9637 <td>
9639 </td>
9640 <td>
9642 </td>
9643 <td>
9644 <p>
9645 Lame delegations received.
9646 </p>
9647 </td>
9648 </tr>
9649 <tr>
9650 <td>
9652 </td>
9653 <td>
9655 </td>
9656 <td>
9657 <p>
9658 Query retries performed.
9659 </p>
9660 </td>
9661 </tr>
9662 <tr>
9663 <td>
9665 </td>
9666 <td>
9668 </td>
9669 <td>
9670 <p>
9671 Queries aborted due to quota control.
9672 </p>
9673 </td>
9674 </tr>
9675 <tr>
9676 <td>
9678 </td>
9679 <td>
9681 </td>
9682 <td>
9683 <p>
9684 Failures in opening query sockets.
9685 One common reason for such failures is a
9686 failure of opening a new socket due to a
9687 limitation on file descriptors.
9688 </p>
9689 </td>
9690 </tr>
9691 <tr>
9692 <td>
9694 </td>
9695 <td>
9697 </td>
9698 <td>
9699 <p>
9700 Query timeouts.
9701 </p>
9702 </td>
9703 </tr>
9704 <tr>
9705 <td>
9707 </td>
9708 <td>
9710 </td>
9711 <td>
9712 <p>
9713 IPv4 NS address fetches invoked.
9714 </p>
9715 </td>
9716 </tr>
9717 <tr>
9718 <td>
9720 </td>
9721 <td>
9723 </td>
9724 <td>
9725 <p>
9726 IPv6 NS address fetches invoked.
9727 </p>
9728 </td>
9729 </tr>
9730 <tr>
9731 <td>
9733 </td>
9734 <td>
9736 </td>
9737 <td>
9738 <p>
9739 IPv4 NS address fetch failed.
9740 </p>
9741 </td>
9742 </tr>
9743 <tr>
9744 <td>
9746 </td>
9747 <td>
9749 </td>
9750 <td>
9751 <p>
9752 IPv6 NS address fetch failed.
9753 </p>
9754 </td>
9755 </tr>
9756 <tr>
9757 <td>
9759 </td>
9760 <td>
9762 </td>
9763 <td>
9764 <p>
9765 DNSSEC validation attempted.
9766 </p>
9767 </td>
9768 </tr>
9769 <tr>
9770 <td>
9772 </td>
9773 <td>
9775 </td>
9776 <td>
9777 <p>
9778 DNSSEC validation succeeded.
9779 </p>
9780 </td>
9781 </tr>
9782 <tr>
9783 <td>
9785 </td>
9786 <td>
9788 </td>
9789 <td>
9790 <p>
9791 DNSSEC validation on negative information succeeded.
9792 </p>
9793 </td>
9794 </tr>
9795 <tr>
9796 <td>
9798 </td>
9799 <td>
9801 </td>
9802 <td>
9803 <p>
9804 DNSSEC validation failed.
9805 </p>
9806 </td>
9807 </tr>
9808 <tr>
9809 <td>
9811 </td>
9812 <td>
9814 </td>
9815 <td>
9816 <p>
9817 Frequency table on round trip times (RTTs) of
9818 queries.
9820 frequency.
9821 In the sequence of
9824 ...,
9827 number of queries whose RTTs are between
9830 For the sake of convenience we define
9832 The last entry should be represented as
9834 number of queries whose RTTs are equal to or over
9836 </p>
9837 </td>
9838 </tr>
9839 </tbody>
9840 </table></div>
9841 </div>
9845 <p>
9846 Socket I/O statistics counters are defined per socket
9847 types, which are
9854 socket module).
9856 represents a socket type.
9857 Not all counters are available for all socket types;
9858 exceptions are noted in the description field.
9859 </p>
9861 <colgroup>
9862 <col>
9863 <col>
9864 </colgroup>
9865 <tbody>
9866 <tr>
9867 <td>
9868 <p>
9870 </p>
9871 </td>
9872 <td>
9873 <p>
9875 </p>
9876 </td>
9877 </tr>
9878 <tr>
9879 <td>
9881 </td>
9882 <td>
9883 <p>
9884 Sockets opened successfully.
9885 This counter is not applicable to the
9887 </p>
9888 </td>
9889 </tr>
9890 <tr>
9891 <td>
9893 </td>
9894 <td>
9895 <p>
9896 Failures of opening sockets.
9897 This counter is not applicable to the
9899 </p>
9900 </td>
9901 </tr>
9902 <tr>
9903 <td>
9905 </td>
9906 <td>
9907 <p>
9908 Sockets closed.
9909 </p>
9910 </td>
9911 </tr>
9912 <tr>
9913 <td>
9915 </td>
9916 <td>
9917 <p>
9918 Failures of binding sockets.
9919 </p>
9920 </td>
9921 </tr>
9922 <tr>
9923 <td>
9925 </td>
9926 <td>
9927 <p>
9928 Failures of connecting sockets.
9929 </p>
9930 </td>
9931 </tr>
9932 <tr>
9933 <td>
9935 </td>
9936 <td>
9937 <p>
9938 Connections established successfully.
9939 </p>
9940 </td>
9941 </tr>
9942 <tr>
9943 <td>
9945 </td>
9946 <td>
9947 <p>
9948 Failures of accepting incoming connection requests.
9949 This counter is not applicable to the
9952 </p>
9953 </td>
9954 </tr>
9955 <tr>
9956 <td>
9958 </td>
9959 <td>
9960 <p>
9961 Incoming connections successfully accepted.
9962 This counter is not applicable to the
9965 </p>
9966 </td>
9967 </tr>
9968 <tr>
9969 <td>
9971 </td>
9972 <td>
9973 <p>
9974 Errors in socket send operations.
9975 This counter corresponds
9978 </p>
9979 </td>
9980 </tr>
9981 <tr>
9982 <td>
9984 </td>
9985 <td>
9986 <p>
9987 Errors in socket receive operations.
9988 This includes errors of send operations on a
9989 connected UDP socket notified by an ICMP error
9990 message.
9991 </p>
9992 </td>
9993 </tr>
9994 </tbody>
9995 </table></div>
9996 </div>
9999 <a name="id2600881"></a>Compatibility with <span class="emphasis"><em>BIND</em></span> 8 Counters</h4></div></div></div>
10000 <p>
10001 Most statistics counters that were available
10004 Here are notes about other counters that do not appear
10005 in these tables.
10006 </p>
10009 <dd><p>
10010 These counters are not supported
10014 </p></dd>
10016 <dd><p>
10017 This counter is accessible in the Incoming Queries section.
10018 </p></dd>
10020 <dd><p>
10021 This counter is accessible in the Incoming Requests section.
10022 </p></dd>
10024 <dd><p>
10025 This counter is not supported
10027 about IP options in the first place.
10028 </p></dd>
10029 </dl></div>
10030 </div>
10031 </div>
10032 </div>
10033 </div>
10035 <hr>
10037 <tr>
10042 </td>
10043 </tr>
10044 <tr>
10045 <td width="40%" align="left" valign="top">Chapter 5. The <acronym class="acronym">BIND</acronym> 9 Lightweight Resolver </td>
10047 <td width="40%" align="right" valign="top"> Chapter 7. <acronym class="acronym">BIND</acronym> 9 Security Considerations</td>
10048 </tr>
10049 </table>
10050 </div>
10051 </body>
10052 </html>