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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <!-- - Copyright (C) 2000-2018 Internet Systems Consortium, Inc. ("ISC") - - This Source Code Form is subject to the terms of the Mozilla Public - License, v. 2.0. If a copy of the MPL was not distributed with this - file, You can obtain one at http://mozilla.org/MPL/2.0/. --> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>lwresd</title> <meta name="generator" content="DocBook XSL Stylesheets V1.78.1"> <link rel="home" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual"> <link rel="up" href="Bv9ARM.ch13.html" title="Manual pages"> <link rel="prev" href="man.dnssec-verify.html" title="dnssec-verify"> <link rel="next" href="man.named.html" title="named"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr><th colspan="3" align="center"><span class="application">lwresd</span></th></tr> <tr> <td width="20%" align="left"> <a accesskey="p" href="man.dnssec-verify.html">Prev</a>�</td> <th width="60%" align="center">Manual pages</th> <td width="20%" align="right">�<a accesskey="n" href="man.named.html">Next</a> </td> </tr> </table> <hr> </div> <div class="refentry"> <a name="man.lwresd"></a><div class="titlepage"></div> <div class="refnamediv"> <h2>Name</h2> <p> <span class="application">lwresd</span> — lightweight resolver daemon </p> </div> <div class="refsynopsisdiv"> <h2>Synopsis</h2> <div class="cmdsynopsis"><p> <code class="command">lwresd</code> [<code class="option">-c <em class="replaceable"><code>config-file</code></em></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">-i <em class="replaceable"><code>pid-file</code></em></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">-p <em class="replaceable"><code>port</code></em></code>] [<code class="option">-s</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">-4</code>] | [<code class="option">-6</code>] ] </p></div> </div> <div class="refsection"> <a name="id-1.14.18.7"></a><h2>DESCRIPTION</h2> <p><span class="command"><strong>lwresd</strong></span> is the daemon providing name lookup services to clients that use the BIND 9 lightweight resolver library. It is essentially a stripped-down, caching-only name server that answers queries using the BIND 9 lightweight resolver protocol rather than the DNS protocol. </p> <p><span class="command"><strong>lwresd</strong></span> listens for resolver queries on a UDP port on the IPv4 loopback interface, 127.0.0.1. This means that <span class="command"><strong>lwresd</strong></span> can only be used by processes running on the local machine. By default, UDP port number 921 is used for lightweight resolver requests and responses. </p> <p> Incoming lightweight resolver requests are decoded by the server which then resolves them using the DNS protocol. When the DNS lookup completes, <span class="command"><strong>lwresd</strong></span> encodes the answers in the lightweight resolver format and returns them to the client that made the request. </p> <p> If <code class="filename">/etc/resolv.conf</code> contains any <code class="option">nameserver</code> entries, <span class="command"><strong>lwresd</strong></span> sends recursive DNS queries to those servers. This is similar to the use of forwarders in a caching name server. If no <code class="option">nameserver</code> entries are present, or if forwarding fails, <span class="command"><strong>lwresd</strong></span> resolves the queries autonomously starting at the root name servers, using a built-in list of root server hints. </p> </div> <div class="refsection"> <a name="id-1.14.18.8"></a><h2>OPTIONS</h2> <div class="variablelist"><dl class="variablelist"> <dt><span class="term">-4</span></dt> <dd> <p> Use IPv4 only even if the host machine is capable of IPv6. <code class="option">-4</code> and <code class="option">-6</code> are mutually exclusive. </p> </dd> <dt><span class="term">-6</span></dt> <dd> <p> Use IPv6 only even if the host machine is capable of IPv4. <code class="option">-4</code> and <code class="option">-6</code> are mutually exclusive. </p> </dd> <dt><span class="term">-c <em class="replaceable"><code>config-file</code></em></span></dt> <dd> <p> Use <em class="replaceable"><code>config-file</code></em> as the configuration file instead of the default, <code class="filename">/etc/lwresd.conf</code>. <code class="option">-c</code> can not be used with <code class="option">-C</code>. </p> </dd> <dt><span class="term">-C <em class="replaceable"><code>config-file</code></em></span></dt> <dd> <p> Use <em class="replaceable"><code>config-file</code></em> as the configuration file instead of the default, <code class="filename">/etc/resolv.conf</code>. <code class="option">-C</code> can not be used with <code class="option">-c</code>. </p> </dd> <dt><span class="term">-d <em class="replaceable"><code>debug-level</code></em></span></dt> <dd> <p> Set the daemon's debug level to <em class="replaceable"><code>debug-level</code></em>. Debugging traces from <span class="command"><strong>lwresd</strong></span> become more verbose as the debug level increases. </p> </dd> <dt><span class="term">-f</span></dt> <dd> <p> Run the server in the foreground (i.e. do not daemonize). </p> </dd> <dt><span class="term">-g</span></dt> <dd> <p> Run the server in the foreground and force all logging to <code class="filename">stderr</code>. </p> </dd> <dt><span class="term">-i <em class="replaceable"><code>pid-file</code></em></span></dt> <dd> <p> Use <em class="replaceable"><code>pid-file</code></em> as the PID file instead of the default, <code class="filename">/var/run/lwresd/lwresd.pid</code>. </p> </dd> <dt><span class="term">-m <em class="replaceable"><code>flag</code></em></span></dt> <dd> <p> Turn on memory usage debugging flags. Possible flags are <em class="replaceable"><code>usage</code></em>, <em class="replaceable"><code>trace</code></em>, <em class="replaceable"><code>record</code></em>, <em class="replaceable"><code>size</code></em>, and <em class="replaceable"><code>mctx</code></em>. These correspond to the ISC_MEM_DEBUGXXXX flags described in <code class="filename"><isc/mem.h></code>. </p> </dd> <dt><span class="term">-n <em class="replaceable"><code>#cpus</code></em></span></dt> <dd> <p> Create <em class="replaceable"><code>#cpus</code></em> worker threads to take advantage of multiple CPUs. If not specified, <span class="command"><strong>lwresd</strong></span> will try to determine the number of CPUs present and create one thread per CPU. If it is unable to determine the number of CPUs, a single worker thread will be created. </p> </dd> <dt><span class="term">-P <em class="replaceable"><code>port</code></em></span></dt> <dd> <p> Listen for lightweight resolver queries on port <em class="replaceable"><code>port</code></em>. If not specified, the default is port 921. </p> </dd> <dt><span class="term">-p <em class="replaceable"><code>port</code></em></span></dt> <dd> <p> Send DNS lookups to port <em class="replaceable"><code>port</code></em>. If not specified, the default is port 53. This provides a way of testing the lightweight resolver daemon with a name server that listens for queries on a non-standard port number. </p> </dd> <dt><span class="term">-s</span></dt> <dd> <p> Write memory usage statistics to <code class="filename">stdout</code> on exit. </p> <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"> <h3 class="title">Note</h3> <p> This option is mainly of interest to BIND 9 developers and may be removed or changed in a future release. </p> </div> </dd> <dt><span class="term">-t <em class="replaceable"><code>directory</code></em></span></dt> <dd> <p>Chroot to <em class="replaceable"><code>directory</code></em> after processing the command line arguments, but before reading the configuration file. </p> <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"> <h3 class="title">Warning</h3> <p> This option should be used in conjunction with the <code class="option">-u</code> option, as chrooting a process running as root doesn't enhance security on most systems; the way <code class="function">chroot(2)</code> is defined allows a process with root privileges to escape a chroot jail. </p> </div> </dd> <dt><span class="term">-u <em class="replaceable"><code>user</code></em></span></dt> <dd> <p>Setuid to <em class="replaceable"><code>user</code></em> after completing privileged operations, such as creating sockets that listen on privileged ports. </p> </dd> <dt><span class="term">-v</span></dt> <dd> <p> Report the version number and exit. </p> </dd> </dl></div> </div> <div class="refsection"> <a name="id-1.14.18.9"></a><h2>FILES</h2> <div class="variablelist"><dl class="variablelist"> <dt><span class="term"><code class="filename">/etc/resolv.conf</code></span></dt> <dd> <p> The default configuration file. </p> </dd> <dt><span class="term"><code class="filename">/var/run/lwresd.pid</code></span></dt> <dd> <p> The default process-id file. </p> </dd> </dl></div> </div> <div class="refsection"> <a name="id-1.14.18.10"></a><h2>SEE ALSO</h2> <p><span class="citerefentry"> <span class="refentrytitle">named</span>(8) </span>, <span class="citerefentry"> <span class="refentrytitle">lwres</span>(3) </span>, <span class="citerefentry"> <span class="refentrytitle">resolver</span>(5) </span>. </p> </div> </div> <div class="navfooter"> <hr> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"> <a accesskey="p" href="man.dnssec-verify.html">Prev</a>�</td> <td width="20%" align="center"><a accesskey="u" href="Bv9ARM.ch13.html">Up</a></td> <td width="40%" align="right">�<a accesskey="n" href="man.named.html">Next</a> </td> </tr> <tr> <td width="40%" align="left" valign="top"> <span class="application">dnssec-verify</span>�</td> <td width="20%" align="center"><a accesskey="h" href="Bv9ARM.html">Home</a></td> <td width="40%" align="right" valign="top">�<span class="application">named</span> </td> </tr> </table> </div> <p xmlns:db="http://docbook.org/ns/docbook" style="text-align: center;">BIND 9.11.4-P2 (Extended Support Version)</p> </body> </html>