named.html revision 6ea2385360e9e2167e65f9286447da9eea189457
75c0816e8295e180f4bc7f10db3d0d880383bc1cMark Andrews - Copyright (C) 2004-2009, 2011, 2013 Internet Systems Consortium, Inc. ("ISC")
75c0816e8295e180f4bc7f10db3d0d880383bc1cMark Andrews - Copyright (C) 2000, 2001, 2003 Internet Software Consortium.
6ea1b817e31b89a627e146fe69e23ea0a64c89ecBob Halley - Permission to use, copy, modify, and/or distribute this software for any
6ea1b817e31b89a627e146fe69e23ea0a64c89ecBob Halley - purpose with or without fee is hereby granted, provided that the above
6ea1b817e31b89a627e146fe69e23ea0a64c89ecBob Halley - copyright notice and this permission notice appear in all copies.
8a66318e41ed14c5a88130e8c362610e8faa2121Mark Andrews - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
8a66318e41ed14c5a88130e8c362610e8faa2121Mark Andrews - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
8a66318e41ed14c5a88130e8c362610e8faa2121Mark Andrews - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
8a66318e41ed14c5a88130e8c362610e8faa2121Mark Andrews - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
8a66318e41ed14c5a88130e8c362610e8faa2121Mark Andrews - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
8a66318e41ed14c5a88130e8c362610e8faa2121Mark Andrews - PERFORMANCE OF THIS SOFTWARE.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews<!-- $Id$ -->
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60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" lang="en">
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews<a name="man.named"></a><div class="titlepage"></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><span class="application">named</span> — Internet domain name server</p>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<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">-D <em class="replaceable"><code>string</code></em></code>] [<code class="option">-E <em class="replaceable"><code>engine-name</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>#listeners</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>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><span><strong class="command">named</strong></span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein is a Domain Name System (DNS) server,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein part of the BIND 9 distribution from ISC. For more
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein information on the DNS, see RFCs 1033, 1034, and 1035.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein When invoked without arguments, <span><strong class="command">named</strong></span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein read the default configuration file
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="filename">/etc/named.conf</code>, read any initial
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein data, and listen for queries.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Use IPv4 only even if the host machine is capable of IPv6.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="option">-4</code> and <code class="option">-6</code> are mutually
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Use IPv6 only even if the host machine is capable of IPv4.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="option">-4</code> and <code class="option">-6</code> are mutually
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="term">-c <em class="replaceable"><code>config-file</code></em></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Use <em class="replaceable"><code>config-file</code></em> as the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein configuration file instead of the default,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="filename">/etc/named.conf</code>. To
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein ensure that reloading the configuration file continues
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to work after the server has changed its working
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein directory due to to a possible
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="option">directory</code> option in the configuration
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein file, <em class="replaceable"><code>config-file</code></em> should be
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein an absolute pathname.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="term">-d <em class="replaceable"><code>debug-level</code></em></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Set the daemon's debug level to <em class="replaceable"><code>debug-level</code></em>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Debugging traces from <span><strong class="command">named</strong></span> become
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein more verbose as the debug level increases.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="term">-D <em class="replaceable"><code>string</code></em></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Specifies a string that is used to identify a instance of
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">named</strong></span> in a process listing. The contents
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein of <em class="replaceable"><code>string</code></em> are
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein not examined.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="term">-E <em class="replaceable"><code>engine-name</code></em></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein When applicable, specifies the hardware to use for
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein cryptographic operations, such as a secure key store used
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein for signing.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein When BIND is built with OpenSSL PKCS#11 support, this defaults
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to the string "pkcs11", which identifies an OpenSSL engine
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein that can drive a cryptographic accelerator or hardware service
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein module. When BIND is built with native PKCS#11 cryptography
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein (--enable-native-pkcs11), it defaults to the path of the PKCS#11
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein provider library specified via "--with-pkcs11".
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Run the server in the foreground (i.e. do not daemonize).
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Run the server in the foreground and force all logging
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="term">-m <em class="replaceable"><code>flag</code></em></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Turn on memory usage debugging flags. Possible flags are
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <em class="replaceable"><code>usage</code></em>,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <em class="replaceable"><code>trace</code></em>,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <em class="replaceable"><code>record</code></em>,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <em class="replaceable"><code>size</code></em>, and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein These correspond to the ISC_MEM_DEBUGXXXX flags described in
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="filename"><isc/mem.h></code>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="term">-n <em class="replaceable"><code>#cpus</code></em></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Create <em class="replaceable"><code>#cpus</code></em> worker threads
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to take advantage of multiple CPUs. If not specified,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">named</strong></span> will try to determine the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein number of CPUs present and create one thread per CPU.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein If it is unable to determine the number of CPUs, a
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein single worker thread will be created.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="term">-p <em class="replaceable"><code>port</code></em></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Listen for queries on port <em class="replaceable"><code>port</code></em>. If not
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein specified, the default is port 53.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Write memory usage statistics to <code class="filename">stdout</code> on exit.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein This option is mainly of interest to BIND 9 developers
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and may be removed or changed in a future release.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="term">-S <em class="replaceable"><code>#max-socks</code></em></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Allow <span><strong class="command">named</strong></span> to use up to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <em class="replaceable"><code>#max-socks</code></em> sockets.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein This option should be unnecessary for the vast majority
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The use of this option could even be harmful because the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein specified value may exceed the limitation of the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein underlying system API.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein It is therefore set only when the default configuration
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein causes exhaustion of file descriptors and the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein operational environment is known to support the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein specified number of sockets.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Note also that the actual maximum number is normally a little
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein fewer than the specified value because
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">named</strong></span> reserves some file descriptors
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein for its internal use.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="term">-t <em class="replaceable"><code>directory</code></em></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to <em class="replaceable"><code>directory</code></em> after
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein processing the command line arguments, but before
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein reading the configuration file.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein This option should be used in conjunction with the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="option">-u</code> option, as chrooting a process
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein running as root doesn't enhance security on most
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein systems; the way <code class="function">chroot(2)</code> is
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein defined allows a process with root privileges to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein escape a chroot jail.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="term">-U <em class="replaceable"><code>#listeners</code></em></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Use <em class="replaceable"><code>#listeners</code></em>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein worker threads to listen for incoming UDP packets on each
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein address. If not specified, <span><strong class="command">named</strong></span> will
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein use the number of detected CPUs. If <code class="option">-n</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein has been set to a higher value than the number of CPUs,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein then <code class="option">-U</code> may be increased as high as that
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews value, but no higher.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="term">-u <em class="replaceable"><code>user</code></em></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to <em class="replaceable"><code>user</code></em> after completing
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein privileged operations, such as creating sockets that
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein listen on privileged ports.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein On Linux, <span><strong class="command">named</strong></span> uses the kernel's
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein capability mechanism to drop all root privileges
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein except the ability to <code class="function">bind(2)</code> to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein privileged port and set process resource limits.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Unfortunately, this means that the <code class="option">-u</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein option only works when <span><strong class="command">named</strong></span> is
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein on kernel 2.2.18 or later, or kernel 2.3.99-pre3 or
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein later, since previous kernels did not allow privileges
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews to be retained after <code class="function">setuid(2)</code>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Report the version number and exit.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews Report the version number and build options, and exit.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="term">-x <em class="replaceable"><code>cache-file</code></em></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Load data from <em class="replaceable"><code>cache-file</code></em> into the