contrib/bind9/doc/arm/man.lwresd.html

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  41 <div class="refentry">
  42 <a name="man.lwresd"></a><div class="titlepage"></div>
  43 <div class="refnamediv">
  44 <h2>Name</h2>
  45 <p><span class="application">lwresd</span> &#8212; lightweight resolver daemon</p>
  46 </div>
  47 <div class="refsynopsisdiv">
  48 <h2>Synopsis</h2>
  49 <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>
  50 </div>
  51 <div class="refsection">
  52 <a name="id-1.14.18.7"></a><h2>DESCRIPTION</h2>
  53 <p><span class="command"><strong>lwresd</strong></span>
  54       is the daemon providing name lookup
  55       services to clients that use the BIND 9 lightweight resolver
  56       library.  It is essentially a stripped-down, caching-only name
  57       server that answers queries using the BIND 9 lightweight
  58       resolver protocol rather than the DNS protocol.
  59     </p>
  60 <p><span class="command"><strong>lwresd</strong></span>
  61       listens for resolver queries on a
  62       UDP port on the IPv4 loopback interface, 127.0.0.1.  This
  63       means that <span class="command"><strong>lwresd</strong></span> can only be used by
  64       processes running on the local machine.  By default, UDP port
  65       number 921 is used for lightweight resolver requests and
  66       responses.
  67     </p>
  68 <p>
  69       Incoming lightweight resolver requests are decoded by the
  70       server which then resolves them using the DNS protocol.  When
  71       the DNS lookup completes, <span class="command"><strong>lwresd</strong></span> encodes
  72       the answers in the lightweight resolver format and returns
  73       them to the client that made the request.
  74     </p>
  75 <p>
  76       If <code class="filename">/etc/resolv.conf</code> contains any
  77       <code class="option">nameserver</code> entries, <span class="command"><strong>lwresd</strong></span>
  78       sends recursive DNS queries to those servers.  This is similar
  79       to the use of forwarders in a caching name server.  If no
  80       <code class="option">nameserver</code> entries are present, or if
  81       forwarding fails, <span class="command"><strong>lwresd</strong></span> resolves the
  82       queries autonomously starting at the root name servers, using
  83       a built-in list of root server hints.
  84     </p>
  85 </div>
  86 <div class="refsection">
  87 <a name="id-1.14.18.8"></a><h2>OPTIONS</h2>
  88 <div class="variablelist"><dl class="variablelist">
  89 <dt><span class="term">-4</span></dt>
  90 <dd><p>
  91             Use IPv4 only even if the host machine is capable of IPv6.
  92             <code class="option">-4</code> and <code class="option">-6</code> are mutually
  93             exclusive.
  94           </p></dd>
  95 <dt><span class="term">-6</span></dt>
  96 <dd><p>
  97             Use IPv6 only even if the host machine is capable of IPv4.
  98             <code class="option">-4</code> and <code class="option">-6</code> are mutually
  99             exclusive.
 100           </p></dd>
 101 <dt><span class="term">-c <em class="replaceable"><code>config-file</code></em></span></dt>
 102 <dd><p>
 103             Use <em class="replaceable"><code>config-file</code></em> as the
 104             configuration file instead of the default,
 105             <code class="filename">/etc/lwresd.conf</code>.
 106
 107             <code class="option">-c</code> can not be used with <code class="option">-C</code>.
 108           </p></dd>
 109 <dt><span class="term">-C <em class="replaceable"><code>config-file</code></em></span></dt>
 110 <dd><p>
 111             Use <em class="replaceable"><code>config-file</code></em> as the
 112             configuration file instead of the default,
 113             <code class="filename">/etc/resolv.conf</code>.
 114             <code class="option">-C</code> can not be used with <code class="option">-c</code>.
 115           </p></dd>
 116 <dt><span class="term">-d <em class="replaceable"><code>debug-level</code></em></span></dt>
 117 <dd><p>
 118             Set the daemon's debug level to <em class="replaceable"><code>debug-level</code></em>.
 119             Debugging traces from <span class="command"><strong>lwresd</strong></span> become
 120                         more verbose as the debug level increases.
 121           </p></dd>
 122 <dt><span class="term">-f</span></dt>
 123 <dd><p>
 124             Run the server in the foreground (i.e. do not daemonize).
 125           </p></dd>
 126 <dt><span class="term">-g</span></dt>
 127 <dd><p>
 128             Run the server in the foreground and force all logging
 129             to <code class="filename">stderr</code>.
 130           </p></dd>
 131 <dt><span class="term">-i <em class="replaceable"><code>pid-file</code></em></span></dt>
 132 <dd><p>
 133             Use <em class="replaceable"><code>pid-file</code></em> as the
 134             PID file instead of the default,
 135             <code class="filename">/var/run/lwresd/lwresd.pid</code>.
 136           </p></dd>
 137 <dt><span class="term">-m <em class="replaceable"><code>flag</code></em></span></dt>
 138 <dd><p>
 139             Turn on memory usage debugging flags.  Possible flags are
 140             <em class="replaceable"><code>usage</code></em>,
 141             <em class="replaceable"><code>trace</code></em>,
 142             <em class="replaceable"><code>record</code></em>,
 143             <em class="replaceable"><code>size</code></em>, and
 144             <em class="replaceable"><code>mctx</code></em>.
 145             These correspond to the ISC_MEM_DEBUGXXXX flags described in
 146             <code class="filename">&lt;isc/mem.h&gt;</code>.
 147           </p></dd>
 148 <dt><span class="term">-n <em class="replaceable"><code>#cpus</code></em></span></dt>
 149 <dd><p>
 150             Create <em class="replaceable"><code>#cpus</code></em> worker threads
 151             to take advantage of multiple CPUs.  If not specified,
 152             <span class="command"><strong>lwresd</strong></span> will try to determine the
 153             number of CPUs present and create one thread per CPU.
 154             If it is unable to determine the number of CPUs, a
 155             single worker thread will be created.
 156           </p></dd>
 157 <dt><span class="term">-P <em class="replaceable"><code>port</code></em></span></dt>
 158 <dd><p>
 159             Listen for lightweight resolver queries on port
 160             <em class="replaceable"><code>port</code></em>.  If
 161                         not specified, the default is port 921.
 162           </p></dd>
 163 <dt><span class="term">-p <em class="replaceable"><code>port</code></em></span></dt>
 164 <dd><p>
 165             Send DNS lookups to port <em class="replaceable"><code>port</code></em>.  If not
 166             specified, the default is port 53.  This provides a
 167             way of testing the lightweight resolver daemon with a
 168             name server that listens for queries on a non-standard
 169             port number.
 170           </p></dd>
 171 <dt><span class="term">-s</span></dt>
 172 <dd>
 173 <p>
 174             Write memory usage statistics to <code class="filename">stdout</code>
 175             on exit.
 176           </p>
 177 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
 178 <h3 class="title">Note</h3>
 179 <p>
 180               This option is mainly of interest to BIND 9 developers
 181               and may be removed or changed in a future release.
 182             </p>
 183 </div>
 184 </dd>
 185 <dt><span class="term">-t <em class="replaceable"><code>directory</code></em></span></dt>
 186 <dd>
 187 <p>Chroot
 188             to <em class="replaceable"><code>directory</code></em> after
 189             processing the command line arguments, but before
 190             reading the configuration file.
 191           </p>
 192 <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
 193 <h3 class="title">Warning</h3>
 194 <p>
 195               This option should be used in conjunction with the
 196               <code class="option">-u</code> option, as chrooting a process
 197               running as root doesn't enhance security on most
 198               systems; the way <code class="function">chroot(2)</code> is
 199               defined allows a process with root privileges to
 200               escape a chroot jail.
 201             </p>
 202 </div>
 203 </dd>
 204 <dt><span class="term">-u <em class="replaceable"><code>user</code></em></span></dt>
 205 <dd><p>Setuid
 206             to <em class="replaceable"><code>user</code></em> after completing
 207             privileged operations, such as creating sockets that
 208             listen on privileged ports.
 209           </p></dd>
 210 <dt><span class="term">-v</span></dt>
 211 <dd><p>
 212             Report the version number and exit.
 213           </p></dd>
 214 </dl></div>
 215 </div>
 216 <div class="refsection">
 217 <a name="id-1.14.18.9"></a><h2>FILES</h2>
 218 <div class="variablelist"><dl class="variablelist">
 219 <dt><span class="term"><code class="filename">/etc/resolv.conf</code></span></dt>
 220 <dd><p>
 221             The default configuration file.
 222           </p></dd>
 223 <dt><span class="term"><code class="filename">/var/run/lwresd.pid</code></span></dt>
 224 <dd><p>
 225             The default process-id file.
 226           </p></dd>
 227 </dl></div>
 228 </div>
 229 <div class="refsection">
 230 <a name="id-1.14.18.10"></a><h2>SEE ALSO</h2>
 231 <p><span class="citerefentry"><span class="refentrytitle">named</span>(8)</span>,
 232       <span class="citerefentry"><span class="refentrytitle">lwres</span>(3)</span>,
 233       <span class="citerefentry"><span class="refentrytitle">resolver</span>(5)</span>.
 234     </p>
 235 </div>
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