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1 .\" $NetBSD: nsupdate.1,v 1.6 2014/12/10 04:37:52 christos Exp $
2 .\"
3 .\" Copyright (C) 2004-2012, 2014 Internet Systems Consortium, Inc. ("ISC")
4 .\" Copyright (C) 2000-2003 Internet Software Consortium.
5 .\"
6 .\" Permission to use, copy, modify, and/or distribute this software for any
7 .\" purpose with or without fee is hereby granted, provided that the above
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18 .\" Id
19 .\"
20 .hy 0
21 .ad l
22 .\" Title: nsupdate
23 .\" Author:
24 .\" Generator: DocBook XSL Stylesheets v1.71.1 <http://docbook.sf.net/>
25 .\" Date: April 18, 2014
26 .\" Manual: BIND9
27 .\" Source: BIND9
28 .\"
29 .TH "NSUPDATE" "1" "April 18, 2014" "BIND9" "BIND9"
30 .\" disable hyphenation
31 .nh
32 .\" disable justification (adjust text to left margin only)
33 .ad l
34 .SH "NAME"
35 nsupdate \- Dynamic DNS update utility
36 .SH "SYNOPSIS"
37 .HP 9
38 \fBnsupdate\fR [\fB\-d\fR] [\fB\-D\fR] [[\fB\-g\fR] | [\fB\-o\fR] | [\fB\-l\fR] | [\fB\-y\ \fR\fB\fI[hmac:]\fR\fIkeyname:secret\fR\fR] | [\fB\-k\ \fR\fB\fIkeyfile\fR\fR]] [\fB\-t\ \fR\fB\fItimeout\fR\fR] [\fB\-u\ \fR\fB\fIudptimeout\fR\fR] [\fB\-r\ \fR\fB\fIudpretries\fR\fR] [\fB\-R\ \fR\fB\fIrandomdev\fR\fR] [\fB\-v\fR] [\fB\-T\fR] [\fB\-P\fR] [\fB\-V\fR] [filename]
39 .SH "DESCRIPTION"
40 .PP
41 \fBnsupdate\fR
42 is used to submit Dynamic DNS Update requests as defined in RFC 2136 to a name server. This allows resource records to be added or removed from a zone without manually editing the zone file. A single update request can contain requests to add or remove more than one resource record.
43 .PP
44 Zones that are under dynamic control via
45 \fBnsupdate\fR
46 or a DHCP server should not be edited by hand. Manual edits could conflict with dynamic updates and cause data to be lost.
47 .PP
48 The resource records that are dynamically added or removed with
49 \fBnsupdate\fR
50 have to be in the same zone. Requests are sent to the zone's master server. This is identified by the MNAME field of the zone's SOA record.
51 .PP
52 The
53 \fB\-d\fR
54 option makes
55 \fBnsupdate\fR
56 operate in debug mode. This provides tracing information about the update requests that are made and the replies received from the name server.
57 .PP
58 The
59 \fB\-D\fR
60 option makes
61 \fBnsupdate\fR
62 report additional debugging information to
63 \fB\-d\fR.
64 .PP
65 The
66 \fB\-L\fR
67 option with an integer argument of zero or higher sets the logging debug level. If zero, logging is disabled.
68 .PP
69 Transaction signatures can be used to authenticate the Dynamic DNS updates. These use the TSIG resource record type described in RFC 2845 or the SIG(0) record described in RFC 2535 and RFC 2931 or GSS\-TSIG as described in RFC 3645. TSIG relies on a shared secret that should only be known to
70 \fBnsupdate\fR
71 and the name server. Currently, the only supported encryption algorithm for TSIG is HMAC\-MD5, which is defined in RFC 2104. Once other algorithms are defined for TSIG, applications will need to ensure they select the appropriate algorithm as well as the key when authenticating each other. For instance, suitable
72 \fBkey\fR
73 and
74 \fBserver\fR
75 statements would be added to
76 \fI/etc/named.conf\fR
77 so that the name server can associate the appropriate secret key and algorithm with the IP address of the client application that will be using TSIG authentication. SIG(0) uses public key cryptography. To use a SIG(0) key, the public key must be stored in a KEY record in a zone served by the name server.
78 \fBnsupdate\fR
79 does not read
80 \fI/etc/named.conf\fR.
81 .PP
82 GSS\-TSIG uses Kerberos credentials. Standard GSS\-TSIG mode is switched on with the
83 \fB\-g\fR
84 flag. A non\-standards\-compliant variant of GSS\-TSIG used by Windows 2000 can be switched on with the
85 \fB\-o\fR
86 flag.
87 .PP
88 \fBnsupdate\fR
89 uses the
90 \fB\-y\fR
91 or
92 \fB\-k\fR
93 option to provide the shared secret needed to generate a TSIG record for authenticating Dynamic DNS update requests, default type HMAC\-MD5. These options are mutually exclusive.
94 .PP
95 When the
96 \fB\-y\fR
97 option is used, a signature is generated from
98 [\fIhmac:\fR]\fIkeyname:secret.\fR
99 \fIkeyname\fR
100 is the name of the key, and
101 \fIsecret\fR
102 is the base64 encoded shared secret.
103 \fIhmac\fR
104 is the name of the key algorithm; valid choices are
105 hmac\-md5,
106 hmac\-sha1,
107 hmac\-sha224,
108 hmac\-sha256,
109 hmac\-sha384, or
110 hmac\-sha512. If
111 \fIhmac\fR
112 is not specified, the default is
113 hmac\-md5. NOTE: Use of the
114 \fB\-y\fR
115 option is discouraged because the shared secret is supplied as a command line argument in clear text. This may be visible in the output from
116 \fBps\fR(1)
117 or in a history file maintained by the user's shell.
118 .PP
119 With the
120 \fB\-k\fR
121 option,
122 \fBnsupdate\fR
123 reads the shared secret from the file
124 \fIkeyfile\fR. Keyfiles may be in two formats: a single file containing a
125 \fInamed.conf\fR\-format
126 \fBkey\fR
127 statement, which may be generated automatically by
128 \fBddns\-confgen\fR, or a pair of files whose names are of the format
129 \fIK{name}.+157.+{random}.key\fR
130 and
131 \fIK{name}.+157.+{random}.private\fR, which can be generated by
132 \fBdnssec\-keygen\fR. The
133 \fB\-k\fR
134 may also be used to specify a SIG(0) key used to authenticate Dynamic DNS update requests. In this case, the key specified is not an HMAC\-MD5 key.
135 .PP
136 \fBnsupdate\fR
137 can be run in a local\-host only mode using the
138 \fB\-l\fR
139 flag. This sets the server address to localhost (disabling the
140 \fBserver\fR
141 so that the server address cannot be overridden). Connections to the local server will use a TSIG key found in
142 \fI/var/run/named/session.key\fR, which is automatically generated by
143 \fBnamed\fR
144 if any local master zone has set
145 \fBupdate\-policy\fR
146 to
147 \fBlocal\fR. The location of this key file can be overridden with the
148 \fB\-k\fR
149 option.
150 .PP
151 By default,
152 \fBnsupdate\fR
153 uses UDP to send update requests to the name server unless they are too large to fit in a UDP request in which case TCP will be used. The
154 \fB\-v\fR
155 option makes
156 \fBnsupdate\fR
157 use a TCP connection. This may be preferable when a batch of update requests is made.
158 .PP
159 The
160 \fB\-p\fR
161 sets the default port number to use for connections to a name server. The default is 53.
162 .PP
163 The
164 \fB\-t\fR
165 option sets the maximum time an update request can take before it is aborted. The default is 300 seconds. Zero can be used to disable the timeout.
166 .PP
167 The
168 \fB\-u\fR
169 option sets the UDP retry interval. The default is 3 seconds. If zero, the interval will be computed from the timeout interval and number of UDP retries.
170 .PP
171 The
172 \fB\-r\fR
173 option sets the number of UDP retries. The default is 3. If zero, only one update request will be made.
174 .PP
175 The
176 \fB\-R \fR\fB\fIrandomdev\fR\fR
177 option specifies a source of randomness. If the operating system does not provide a
178 \fI/dev/random\fR
179 or equivalent device, the default source of randomness is keyboard input.
180 \fIrandomdev\fR
181 specifies the name of a character device or file containing random data to be used instead of the default. The special value
182 \fIkeyboard\fR
183 indicates that keyboard input should be used. This option may be specified multiple times.
184 .PP
185 Other types can be entered using "TYPEXXXXX" where "XXXXX" is the decimal value of the type with no leading zeros. The rdata, if present, will be parsed using the UNKNOWN rdata format, (<backslash> <hash> <space> <length> <space> <hexstring>).
186 .PP
187 The
188 \fB\-T\fR
189 and
190 \fB\-P\fR
191 options print out lists of non\-meta types for which the type\-specific presentation formats are known.
192 \fB\-T\fR
193 prints out the list of IANA\-assigned types.
194 \fB\-P\fR
195 prints out the list of private types specific to
196 \fBnamed\fR. These options may be combined.
197 \fBnsupdate\fR
198 will exit after the lists are printed.
199 .PP
200 The \-V option causes
201 \fBnsupdate\fR
202 to print the version number and exit.
203 .SH "INPUT FORMAT"
204 .PP
205 \fBnsupdate\fR
206 reads input from
207 \fIfilename\fR
208 or standard input. Each command is supplied on exactly one line of input. Some commands are for administrative purposes. The others are either update instructions or prerequisite checks on the contents of the zone. These checks set conditions that some name or set of resource records (RRset) either exists or is absent from the zone. These conditions must be met if the entire update request is to succeed. Updates will be rejected if the tests for the prerequisite conditions fail.
209 .PP
210 Every update request consists of zero or more prerequisites and zero or more updates. This allows a suitably authenticated update request to proceed if some specified resource records are present or missing from the zone. A blank input line (or the
211 \fBsend\fR
212 command) causes the accumulated commands to be sent as one Dynamic DNS update request to the name server.
213 .PP
214 The command formats and their meaning are as follows:
215 .PP
216 \fBserver\fR {servername} [port]
217 .RS 4
218 Sends all dynamic update requests to the name server
219 \fIservername\fR. When no server statement is provided,
220 \fBnsupdate\fR
221 will send updates to the master server of the correct zone. The MNAME field of that zone's SOA record will identify the master server for that zone.
222 \fIport\fR
223 is the port number on
224 \fIservername\fR
225 where the dynamic update requests get sent. If no port number is specified, the default DNS port number of 53 is used.
226 .RE
227 .PP
228 \fBlocal\fR {address} [port]
229 .RS 4
230 Sends all dynamic update requests using the local
231 \fIaddress\fR. When no local statement is provided,
232 \fBnsupdate\fR
233 will send updates using an address and port chosen by the system.
234 \fIport\fR
235 can additionally be used to make requests come from a specific port. If no port number is specified, the system will assign one.
236 .RE
237 .PP
238 \fBzone\fR {zonename}
239 .RS 4
240 Specifies that all updates are to be made to the zone
241 \fIzonename\fR. If no
242 \fIzone\fR
243 statement is provided,
244 \fBnsupdate\fR
245 will attempt determine the correct zone to update based on the rest of the input.
246 .RE
247 .PP
248 \fBclass\fR {classname}
249 .RS 4
250 Specify the default class. If no
251 \fIclass\fR
252 is specified, the default class is
253 \fIIN\fR.
254 .RE
255 .PP
256 \fBttl\fR {seconds}
257 .RS 4
258 Specify the default time to live for records to be added. The value
259 \fInone\fR
260 will clear the default ttl.
261 .RE
262 .PP
263 \fBkey\fR [hmac:] {keyname} {secret}
264 .RS 4
265 Specifies that all updates are to be TSIG\-signed using the
266 \fIkeyname\fR
267 \fIsecret\fR
268 pair. If
269 \fIhmac\fR
270 is specified, then it sets the signing algorithm in use; the default is
271 hmac\-md5. The
272 \fBkey\fR
273 command overrides any key specified on the command line via
274 \fB\-y\fR
275 or
276 \fB\-k\fR.
277 .RE
278 .PP
279 \fBgsstsig\fR
280 .RS 4
281 Use GSS\-TSIG to sign the updated. This is equivalent to specifying
282 \fB\-g\fR
283 on the commandline.
284 .RE
285 .PP
286 \fBoldgsstsig\fR
287 .RS 4
288 Use the Windows 2000 version of GSS\-TSIG to sign the updated. This is equivalent to specifying
289 \fB\-o\fR
290 on the commandline.
291 .RE
292 .PP
293 \fBrealm\fR {[realm_name]}
294 .RS 4
295 When using GSS\-TSIG use
296 \fIrealm_name\fR
297 rather than the default realm in
298 \fIkrb5.conf\fR. If no realm is specified the saved realm is cleared.
299 .RE
300 .PP
301 \fB[prereq]\fR\fB nxdomain\fR {domain\-name}
302 .RS 4
303 Requires that no resource record of any type exists with name
304 \fIdomain\-name\fR.
305 .RE
306 .PP
307 \fB[prereq]\fR\fB yxdomain\fR {domain\-name}
308 .RS 4
309 Requires that
310 \fIdomain\-name\fR
311 exists (has as at least one resource record, of any type).
312 .RE
313 .PP
314 \fB[prereq]\fR\fB nxrrset\fR {domain\-name} [class] {type}
315 .RS 4
316 Requires that no resource record exists of the specified
317 \fItype\fR,
318 \fIclass\fR
319 and
320 \fIdomain\-name\fR. If
321 \fIclass\fR
322 is omitted, IN (internet) is assumed.
323 .RE
324 .PP
325 \fB[prereq]\fR\fB yxrrset\fR {domain\-name} [class] {type}
326 .RS 4
327 This requires that a resource record of the specified
328 \fItype\fR,
329 \fIclass\fR
330 and
331 \fIdomain\-name\fR
332 must exist. If
333 \fIclass\fR
334 is omitted, IN (internet) is assumed.
335 .RE
336 .PP
337 \fB[prereq]\fR\fB yxrrset\fR {domain\-name} [class] {type} {data...}
338 .RS 4
339 The
340 \fIdata\fR
341 from each set of prerequisites of this form sharing a common
342 \fItype\fR,
343 \fIclass\fR, and
344 \fIdomain\-name\fR
345 are combined to form a set of RRs. This set of RRs must exactly match the set of RRs existing in the zone at the given
346 \fItype\fR,
347 \fIclass\fR, and
348 \fIdomain\-name\fR. The
349 \fIdata\fR
350 are written in the standard text representation of the resource record's RDATA.
351 .RE
352 .PP
353 \fB[update]\fR\fB del\fR\fB[ete]\fR {domain\-name} [ttl] [class] [type\ [data...]]
354 .RS 4
355 Deletes any resource records named
356 \fIdomain\-name\fR. If
357 \fItype\fR
358 and
359 \fIdata\fR
360 is provided, only matching resource records will be removed. The internet class is assumed if
361 \fIclass\fR
362 is not supplied. The
363 \fIttl\fR
364 is ignored, and is only allowed for compatibility.
365 .RE
366 .PP
367 \fB[update]\fR\fB add\fR {domain\-name} {ttl} [class] {type} {data...}
368 .RS 4
369 Adds a new resource record with the specified
370 \fIttl\fR,
371 \fIclass\fR
372 and
373 \fIdata\fR.
374 .RE
375 .PP
376 \fBshow\fR
377 .RS 4
378 Displays the current message, containing all of the prerequisites and updates specified since the last send.
379 .RE
380 .PP
381 \fBsend\fR
382 .RS 4
383 Sends the current message. This is equivalent to entering a blank line.
384 .RE
385 .PP
386 \fBanswer\fR
387 .RS 4
388 Displays the answer.
389 .RE
390 .PP
391 \fBdebug\fR
392 .RS 4
393 Turn on debugging.
394 .RE
395 .PP
396 \fBversion\fR
397 .RS 4
398 Print version number.
399 .RE
400 .PP
401 \fBhelp\fR
402 .RS 4
403 Print a list of commands.
404 .RE
405 .PP
406 Lines beginning with a semicolon are comments and are ignored.
407 .SH "EXAMPLES"
408 .PP
409 The examples below show how
410 \fBnsupdate\fR
411 could be used to insert and delete resource records from the
412 \fBexample.com\fR
413 zone. Notice that the input in each example contains a trailing blank line so that a group of commands are sent as one dynamic update request to the master name server for
414 \fBexample.com\fR.
415 .sp
416 .RS 4
417 .nf
418 # nsupdate
419 > update delete oldhost.example.com A
420 > update add newhost.example.com 86400 A 172.16.1.1
421 > send
422 .fi
423 .RE
424 .sp
425 .PP
426 Any A records for
427 \fBoldhost.example.com\fR
428 are deleted. And an A record for
429 \fBnewhost.example.com\fR
430 with IP address 172.16.1.1 is added. The newly\-added record has a 1 day TTL (86400 seconds).
431 .sp
432 .RS 4
433 .nf
434 # nsupdate
435 > prereq nxdomain nickname.example.com
436 > update add nickname.example.com 86400 CNAME somehost.example.com
437 > send
438 .fi
439 .RE
440 .sp
441 .PP
442 The prerequisite condition gets the name server to check that there are no resource records of any type for
443 \fBnickname.example.com\fR. If there are, the update request fails. If this name does not exist, a CNAME for it is added. This ensures that when the CNAME is added, it cannot conflict with the long\-standing rule in RFC 1034 that a name must not exist as any other record type if it exists as a CNAME. (The rule has been updated for DNSSEC in RFC 2535 to allow CNAMEs to have RRSIG, DNSKEY and NSEC records.)
444 .SH "FILES"
445 .PP
446 \fB/etc/resolv.conf\fR
447 .RS 4
448 used to identify default name server
449 .RE
450 .PP
451 \fB/var/run/named/session.key\fR
452 .RS 4
453 sets the default TSIG key for use in local\-only mode
454 .RE
455 .PP
456 \fBK{name}.+157.+{random}.key\fR
457 .RS 4
458 base\-64 encoding of HMAC\-MD5 key created by
459 \fBdnssec\-keygen\fR(8).
460 .RE
461 .PP
462 \fBK{name}.+157.+{random}.private\fR
463 .RS 4
464 base\-64 encoding of HMAC\-MD5 key created by
465 \fBdnssec\-keygen\fR(8).
466 .RE
467 .SH "SEE ALSO"
468 .PP
469 RFC 2136,
470 RFC 3007,
471 RFC 2104,
472 RFC 2845,
473 RFC 1034,
474 RFC 2535,
475 RFC 2931,
476 \fBnamed\fR(8),
477 \fBddns\-confgen\fR(8),
478 \fBdnssec\-keygen\fR(8).
479 .SH "BUGS"
480 .PP
481 The TSIG key is redundantly stored in two separate files. This is a consequence of nsupdate using the DST library for its cryptographic operations, and may change in future releases.
482 .SH "COPYRIGHT"
483 Copyright \(co 2004\-2012, 2014 Internet Systems Consortium, Inc. ("ISC")
484 .br
485 Copyright \(co 2000\-2003 Internet Software Consortium.
486 .br