named.html revision a9a054302dd8a52fa9023cc98cc565e9c0008527
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw - Copyright (C) 2004-2009 Internet Systems Consortium, Inc. ("ISC")
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw - Copyright (C) 2000, 2001, 2003 Internet Software Consortium.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw - Permission to use, copy, modify, and distribute this software for any
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw - purpose with or without fee is hereby granted, provided that the above
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw - copyright notice and this permission notice appear in all copies.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw - PERFORMANCE OF THIS SOFTWARE.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<!-- $Id: named.html,v 1.31 2009/05/22 01:14:49 tbox Exp $ -->
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
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d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" lang="en">
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<p><span class="application">named</span> — Internet domain name server</p>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<div class="cmdsynopsis"><p><code class="command">named</code> [<code class="option">-4</code>] [<code class="option">-6</code>] [<code class="option">-c <em class="replaceable"><code>config-file</code></em></code>] [<code class="option">-d <em class="replaceable"><code>debug-level</code></em></code>] [<code class="option">-f</code>] [<code class="option">-g</code>] [<code class="option">-m <em class="replaceable"><code>flag</code></em></code>] [<code class="option">-n <em class="replaceable"><code>#cpus</code></em></code>] [<code class="option">-p <em class="replaceable"><code>port</code></em></code>] [<code class="option">-s</code>] [<code class="option">-S <em class="replaceable"><code>#max-socks</code></em></code>] [<code class="option">-t <em class="replaceable"><code>directory</code></em></code>] [<code class="option">-u <em class="replaceable"><code>user</code></em></code>] [<code class="option">-v</code>] [<code class="option">-V</code>] [<code class="option">-x <em class="replaceable"><code>cache-file</code></em></code>]</p></div>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw is a Domain Name System (DNS) server,
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw part of the BIND 9 distribution from ISC. For more
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw information on the DNS, see RFCs 1033, 1034, and 1035.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw When invoked without arguments, <span><strong class="command">named</strong></span>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw read the default configuration file
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <code class="filename">/etc/named.conf</code>, read any initial
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw data, and listen for queries.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Use IPv4 only even if the host machine is capable of IPv6.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <code class="option">-4</code> and <code class="option">-6</code> are mutually
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw exclusive.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Use IPv6 only even if the host machine is capable of IPv4.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <code class="option">-4</code> and <code class="option">-6</code> are mutually
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw exclusive.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<dt><span class="term">-c <em class="replaceable"><code>config-file</code></em></span></dt>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Use <em class="replaceable"><code>config-file</code></em> as the
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw configuration file instead of the default,
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw ensure that reloading the configuration file continues
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw to work after the server has changed its working
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw directory due to to a possible
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <code class="option">directory</code> option in the configuration
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw file, <em class="replaceable"><code>config-file</code></em> should be
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw an absolute pathname.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<dt><span class="term">-d <em class="replaceable"><code>debug-level</code></em></span></dt>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Set the daemon's debug level to <em class="replaceable"><code>debug-level</code></em>.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Debugging traces from <span><strong class="command">named</strong></span> become
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw more verbose as the debug level increases.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Run the server in the foreground (i.e. do not daemonize).
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Run the server in the foreground and force all logging
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<dt><span class="term">-m <em class="replaceable"><code>flag</code></em></span></dt>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Turn on memory usage debugging flags. Possible flags are
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw These correspond to the ISC_MEM_DEBUGXXXX flags described in
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<dt><span class="term">-n <em class="replaceable"><code>#cpus</code></em></span></dt>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Create <em class="replaceable"><code>#cpus</code></em> worker threads
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw to take advantage of multiple CPUs. If not specified,
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <span><strong class="command">named</strong></span> will try to determine the
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw number of CPUs present and create one thread per CPU.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw If it is unable to determine the number of CPUs, a
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw single worker thread will be created.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<dt><span class="term">-p <em class="replaceable"><code>port</code></em></span></dt>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Listen for queries on port <em class="replaceable"><code>port</code></em>. If not
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw specified, the default is port 53.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Write memory usage statistics to <code class="filename">stdout</code> on exit.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw This option is mainly of interest to BIND 9 developers
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw and may be removed or changed in a future release.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<dt><span class="term">-S <em class="replaceable"><code>#max-socks</code></em></span></dt>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Allow <span><strong class="command">named</strong></span> to use up to
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <em class="replaceable"><code>#max-socks</code></em> sockets.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw This option should be unnecessary for the vast majority
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw The use of this option could even be harmful because the
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw specified value may exceed the limitation of the
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw underlying system API.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw It is therefore set only when the default configuration
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw causes exhaustion of file descriptors and the
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw operational environment is known to support the
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw specified number of sockets.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Note also that the actual maximum number is normally a little
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw fewer than the specified value because
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <span><strong class="command">named</strong></span> reserves some file descriptors
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw for its internal use.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<dt><span class="term">-t <em class="replaceable"><code>directory</code></em></span></dt>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw to <em class="replaceable"><code>directory</code></em> after
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw processing the command line arguments, but before
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw reading the configuration file.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw This option should be used in conjunction with the
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <code class="option">-u</code> option, as chrooting a process
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw running as root doesn't enhance security on most
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw systems; the way <code class="function">chroot(2)</code> is
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw defined allows a process with root privileges to
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw escape a chroot jail.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<dt><span class="term">-u <em class="replaceable"><code>user</code></em></span></dt>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw to <em class="replaceable"><code>user</code></em> after completing
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw privileged operations, such as creating sockets that
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw listen on privileged ports.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw On Linux, <span><strong class="command">named</strong></span> uses the kernel's
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw capability mechanism to drop all root privileges
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw except the ability to <code class="function">bind(2)</code> to
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw privileged port and set process resource limits.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Unfortunately, this means that the <code class="option">-u</code>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw option only works when <span><strong class="command">named</strong></span> is
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw on kernel 2.2.18 or later, or kernel 2.3.99-pre3 or
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw later, since previous kernels did not allow privileges
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw to be retained after <code class="function">setuid(2)</code>.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Report the version number and exit.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Report the version number and build options, and exit.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<dt><span class="term">-x <em class="replaceable"><code>cache-file</code></em></span></dt>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Load data from <em class="replaceable"><code>cache-file</code></em> into the
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw cache of the default view.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw This option must not be used. It is only of interest
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw to BIND 9 developers and may be removed or changed in a
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw future release.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw In routine operation, signals should not be used to control
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw the nameserver; <span><strong class="command">rndc</strong></span> should be used
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Force a reload of the server.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw Shut down the server.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw The result of sending any other signals to the server is undefined.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw The <span><strong class="command">named</strong></span> configuration file is too complex
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw to describe in detail here. A complete description is provided
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <em class="citetitle">BIND 9 Administrator Reference Manual</em>.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <span><strong class="command">named</strong></span> inherits the <code class="function">umask</code>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw (file creation mode mask) from the parent process. If files
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw created by <span><strong class="command">named</strong></span>, such as journal files,
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw need to have custom permissions, the <code class="function">umask</code>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw should be set explicitly in the script used to start the
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <span><strong class="command">named</strong></span> process.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<dt><span class="term"><code class="filename">/etc/named.conf</code></span></dt>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw The default configuration file.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<dt><span class="term"><code class="filename">/var/run/named/named.pid</code></span></dt>
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw The default process-id file.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <span class="citerefentry"><span class="refentrytitle">named-checkconf</span>(8)</span>,
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <span class="citerefentry"><span class="refentrytitle">named-checkzone</span>(8)</span>,
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <span class="citerefentry"><span class="refentrytitle">rndc</span>(8)</span>,
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <span class="citerefentry"><span class="refentrytitle">lwresd</span>(8)</span>,
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <span class="citerefentry"><span class="refentrytitle">named.conf</span>(5)</span>,
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw <em class="citetitle">BIND 9 Administrator Reference Manual</em>.
d39a76e7b087a3d0927cbe6898dc0a6770fa6c68xw<p><span class="corpauthor">Internet Systems Consortium</span>