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21 <!-- Id: named.docbook,v 1.26 2009/10/05 17:30:49 fdupont Exp -->
22 <refentry id="man.named">
24 <date>May 21, 2009</date>
28 <refentrytitle><application>named</application></refentrytitle>
29 <manvolnum>8</manvolnum>
30 <refmiscinfo>BIND9</refmiscinfo>
34 <refname><application>named</application></refname>
35 <refpurpose>Internet domain name server</refpurpose>
46 <holder>Internet Systems Consortium, Inc. ("ISC")</holder>
52 <holder>Internet Software Consortium.</holder>
58 <command>named</command>
59 <arg><option>-4</option></arg>
60 <arg><option>-6</option></arg>
61 <arg><option>-c <replaceable class="parameter">config-file</replaceable></option></arg>
62 <arg><option>-d <replaceable class="parameter">debug-level</replaceable></option></arg>
63 <arg><option>-E <replaceable class="parameter">engine-name</replaceable></option></arg>
64 <arg><option>-f</option></arg>
65 <arg><option>-g</option></arg>
66 <arg><option>-m <replaceable class="parameter">flag</replaceable></option></arg>
67 <arg><option>-n <replaceable class="parameter">#cpus</replaceable></option></arg>
68 <arg><option>-p <replaceable class="parameter">port</replaceable></option></arg>
69 <arg><option>-s</option></arg>
70 <arg><option>-S <replaceable class="parameter">#max-socks</replaceable></option></arg>
71 <arg><option>-t <replaceable class="parameter">directory</replaceable></option></arg>
72 <arg><option>-u <replaceable class="parameter">user</replaceable></option></arg>
73 <arg><option>-v</option></arg>
74 <arg><option>-V</option></arg>
75 <arg><option>-x <replaceable class="parameter">cache-file</replaceable></option></arg>
80 <title>DESCRIPTION</title>
81 <para><command>named</command>
82 is a Domain Name System (DNS) server,
83 part of the BIND 9 distribution from ISC. For more
84 information on the DNS, see RFCs 1033, 1034, and 1035.
87 When invoked without arguments, <command>named</command>
89 read the default configuration file
90 <filename>/etc/named.conf</filename>, read any initial
91 data, and listen for queries.
96 <title>OPTIONS</title>
103 Use IPv4 only even if the host machine is capable of IPv6.
104 <option>-4</option> and <option>-6</option> are mutually
114 Use IPv6 only even if the host machine is capable of IPv4.
115 <option>-4</option> and <option>-6</option> are mutually
122 <term>-c <replaceable class="parameter">config-file</replaceable></term>
125 Use <replaceable class="parameter">config-file</replaceable> as the
126 configuration file instead of the default,
127 <filename>/etc/named.conf</filename>. To
128 ensure that reloading the configuration file continues
129 to work after the server has changed its working
130 directory due to to a possible
131 <option>directory</option> option in the configuration
132 file, <replaceable class="parameter">config-file</replaceable> should be
133 an absolute pathname.
139 <term>-d <replaceable class="parameter">debug-level</replaceable></term>
142 Set the daemon's debug level to <replaceable class="parameter">debug-level</replaceable>.
143 Debugging traces from <command>named</command> become
144 more verbose as the debug level increases.
150 <term>-E <replaceable class="parameter">engine-name</replaceable></term>
153 Use a crypto hardware (OpenSSL engine) for the crypto operations
154 it supports, for instance re-signing with private keys from
155 a secure key store. When compiled with PKCS#11 support
156 <replaceable class="parameter">engine-name</replaceable>
157 defaults to pkcs11, the empty name resets it to no engine.
166 Run the server in the foreground (i.e. do not daemonize).
175 Run the server in the foreground and force all logging
176 to <filename>stderr</filename>.
182 <term>-m <replaceable class="parameter">flag</replaceable></term>
185 Turn on memory usage debugging flags. Possible flags are
186 <replaceable class="parameter">usage</replaceable>,
187 <replaceable class="parameter">trace</replaceable>,
188 <replaceable class="parameter">record</replaceable>,
189 <replaceable class="parameter">size</replaceable>, and
190 <replaceable class="parameter">mctx</replaceable>.
191 These correspond to the ISC_MEM_DEBUGXXXX flags described in
192 <filename><isc/mem.h></filename>.
198 <term>-n <replaceable class="parameter">#cpus</replaceable></term>
201 Create <replaceable class="parameter">#cpus</replaceable> worker threads
202 to take advantage of multiple CPUs. If not specified,
203 <command>named</command> will try to determine the
204 number of CPUs present and create one thread per CPU.
205 If it is unable to determine the number of CPUs, a
206 single worker thread will be created.
212 <term>-p <replaceable class="parameter">port</replaceable></term>
215 Listen for queries on port <replaceable class="parameter">port</replaceable>. If not
216 specified, the default is port 53.
225 Write memory usage statistics to <filename>stdout</filename> on exit.
229 This option is mainly of interest to BIND 9 developers
230 and may be removed or changed in a future release.
237 <term>-S <replaceable class="parameter">#max-socks</replaceable></term>
240 Allow <command>named</command> to use up to
241 <replaceable class="parameter">#max-socks</replaceable> sockets.
245 This option should be unnecessary for the vast majority
247 The use of this option could even be harmful because the
248 specified value may exceed the limitation of the
249 underlying system API.
250 It is therefore set only when the default configuration
251 causes exhaustion of file descriptors and the
252 operational environment is known to support the
253 specified number of sockets.
254 Note also that the actual maximum number is normally a little
255 fewer than the specified value because
256 <command>named</command> reserves some file descriptors
257 for its internal use.
264 <term>-t <replaceable class="parameter">directory</replaceable></term>
267 to <replaceable class="parameter">directory</replaceable> after
268 processing the command line arguments, but before
269 reading the configuration file.
273 This option should be used in conjunction with the
274 <option>-u</option> option, as chrooting a process
275 running as root doesn't enhance security on most
276 systems; the way <function>chroot(2)</function> is
277 defined allows a process with root privileges to
278 escape a chroot jail.
285 <term>-u <replaceable class="parameter">user</replaceable></term>
288 to <replaceable class="parameter">user</replaceable> after completing
289 privileged operations, such as creating sockets that
290 listen on privileged ports.
294 On Linux, <command>named</command> uses the kernel's
295 capability mechanism to drop all root privileges
296 except the ability to <function>bind(2)</function> to
298 privileged port and set process resource limits.
299 Unfortunately, this means that the <option>-u</option>
300 option only works when <command>named</command> is
302 on kernel 2.2.18 or later, or kernel 2.3.99-pre3 or
303 later, since previous kernels did not allow privileges
304 to be retained after <function>setuid(2)</function>.
314 Report the version number and exit.
323 Report the version number and build options, and exit.
329 <term>-x <replaceable class="parameter">cache-file</replaceable></term>
332 Load data from <replaceable class="parameter">cache-file</replaceable> into the
333 cache of the default view.
337 This option must not be used. It is only of interest
338 to BIND 9 developers and may be removed or changed in a
350 <title>SIGNALS</title>
352 In routine operation, signals should not be used to control
353 the nameserver; <command>rndc</command> should be used
363 Force a reload of the server.
369 <term>SIGINT, SIGTERM</term>
372 Shut down the server.
380 The result of sending any other signals to the server is undefined.
386 <title>CONFIGURATION</title>
388 The <command>named</command> configuration file is too complex
389 to describe in detail here. A complete description is provided
391 <citetitle>BIND 9 Administrator Reference Manual</citetitle>.
395 <command>named</command> inherits the <function>umask</function>
396 (file creation mode mask) from the parent process. If files
397 created by <command>named</command>, such as journal files,
398 need to have custom permissions, the <function>umask</function>
399 should be set explicitly in the script used to start the
400 <command>named</command> process.
411 <term><filename>/etc/named.conf</filename></term>
414 The default configuration file.
420 <term><filename>/var/run/named/named.pid</filename></term>
423 The default process-id file.
433 <title>SEE ALSO</title>
434 <para><citetitle>RFC 1033</citetitle>,
435 <citetitle>RFC 1034</citetitle>,
436 <citetitle>RFC 1035</citetitle>,
438 <refentrytitle>named-checkconf</refentrytitle>
439 <manvolnum>8</manvolnum>
442 <refentrytitle>named-checkzone</refentrytitle>
443 <manvolnum>8</manvolnum>
446 <refentrytitle>rndc</refentrytitle>
447 <manvolnum>8</manvolnum>
450 <refentrytitle>lwresd</refentrytitle>
451 <manvolnum>8</manvolnum>
454 <refentrytitle>named.conf</refentrytitle>
455 <manvolnum>5</manvolnum>
457 <citetitle>BIND 9 Administrator Reference Manual</citetitle>.
462 <title>AUTHOR</title>
463 <para><corpauthor>Internet Systems Consortium</corpauthor>