acpi.4: Add some missing references.
[dragonfly.git] / contrib / bind-9.3 / bin / named / lwresd.html
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17 <!-- $Id: lwresd.html,v 1.4.2.1.4.10 2006/06/29 13:02:30 marka Exp $ -->
18 <html>
19 <head>
20 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
21 <title>lwresd</title>
22 <meta name="generator" content="DocBook XSL Stylesheets V1.70.1">
23 </head>
24 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" lang="en">
25 <a name="id2482688"></a><div class="titlepage"></div>
26 <div class="refnamediv">
27 <h2>Name</h2>
28 <p><span class="application">lwresd</span> &#8212; lightweight resolver daemon</p>
29 </div>
30 <div class="refsynopsisdiv">
31 <h2>Synopsis</h2>
32 <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">-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">-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>]</p></div>
33 </div>
34 <div class="refsect1" lang="en">
35 <a name="id2549484"></a><h2>DESCRIPTION</h2>
36 <p>
37         <span><strong class="command">lwresd</strong></span> is the daemon providing name lookup
38         services to clients that use the BIND 9 lightweight resolver
39         library.  It is essentially a stripped-down, caching-only name
40         server that answers queries using the BIND 9 lightweight
41         resolver protocol rather than the DNS protocol.
42     </p>
43 <p>
44         <span><strong class="command">lwresd</strong></span> listens for resolver queries on a
45         UDP port on the IPv4 loopback interface, 127.0.0.1.  This
46         means that <span><strong class="command">lwresd</strong></span> can only be used by
47         processes running on the local machine.  By default UDP port
48         number 921 is used for lightweight resolver requests and
49         responses.
50     </p>
51 <p>
52         Incoming lightweight resolver requests are decoded by the
53         server which then resolves them using the DNS protocol.  When
54         the DNS lookup completes, <span><strong class="command">lwresd</strong></span> encodes
55         the answers in the lightweight resolver format and returns
56         them to the client that made the request.
57     </p>
58 <p>
59         If <code class="filename">/etc/resolv.conf</code> contains any
60         <code class="option">nameserver</code> entries, <span><strong class="command">lwresd</strong></span>
61         sends recursive DNS queries to those servers.  This is similar
62         to the use of forwarders in a caching name server.  If no
63         <code class="option">nameserver</code> entries are present, or if
64         forwarding fails, <span><strong class="command">lwresd</strong></span> resolves the
65         queries autonomously starting at the root name servers, using
66         a built-in list of root server hints.
67     </p>
68 </div>
69 <div class="refsect1" lang="en">
70 <a name="id2549533"></a><h2>OPTIONS</h2>
71 <div class="variablelist"><dl>
72 <dt><span class="term">-C <em class="replaceable"><code>config-file</code></em></span></dt>
73 <dd><p>
74                 Use <em class="replaceable"><code>config-file</code></em> as the
75                 configuration file instead of the default,
76                 <code class="filename">/etc/resolv.conf</code>.
77           </p></dd>
78 <dt><span class="term">-d <em class="replaceable"><code>debug-level</code></em></span></dt>
79 <dd><p>
80                 Set the daemon's debug level to <em class="replaceable"><code>debug-level</code></em>.
81                 Debugging traces from <span><strong class="command">lwresd</strong></span> become
82                 more verbose as the debug level increases.
83           </p></dd>
84 <dt><span class="term">-f</span></dt>
85 <dd><p>
86                 Run the server in the foreground (i.e. do not daemonize).
87           </p></dd>
88 <dt><span class="term">-g</span></dt>
89 <dd><p>
90                 Run the server in the foreground and force all logging
91                 to <code class="filename">stderr</code>.
92           </p></dd>
93 <dt><span class="term">-n <em class="replaceable"><code>#cpus</code></em></span></dt>
94 <dd><p>
95                 Create <em class="replaceable"><code>#cpus</code></em> worker threads
96                 to take advantage of multiple CPUs.  If not specified,
97                 <span><strong class="command">lwresd</strong></span> will try to determine the
98                 number of CPUs present and create one thread per CPU.
99                 If it is unable to determine the number of CPUs, a
100                 single worker thread will be created.
101           </p></dd>
102 <dt><span class="term">-P <em class="replaceable"><code>port</code></em></span></dt>
103 <dd><p>
104                 Listen for lightweight resolver queries on port
105                 <em class="replaceable"><code>port</code></em>.  If
106                 not specified, the default is port 921.
107           </p></dd>
108 <dt><span class="term">-p <em class="replaceable"><code>port</code></em></span></dt>
109 <dd><p>
110                 Send DNS lookups to port <em class="replaceable"><code>port</code></em>.  If not
111                 specified, the default is port 53.  This provides a
112                 way of testing the lightweight resolver daemon with a
113                 name server that listens for queries on a non-standard
114                 port number.
115           </p></dd>
116 <dt><span class="term">-s</span></dt>
117 <dd>
118 <p>
119                 Write memory usage statistics to <code class="filename">stdout</code>
120                 on exit.
121           </p>
122 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
123 <h3 class="title">Note</h3>
124 <p>
125                 This option is mainly of interest to BIND 9 developers
126                 and may be removed or changed in a future release.
127             </p>
128 </div>
129 </dd>
130 <dt><span class="term">-t <em class="replaceable"><code>directory</code></em></span></dt>
131 <dd>
132 <p>
133                 <code class="function">chroot()</code> to <em class="replaceable"><code>directory</code></em> after
134                 processing the command line arguments, but before
135                 reading the configuration file.
136           </p>
137 <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
138 <h3 class="title">Warning</h3>
139 <p>
140                 This option should be used in conjunction with the
141                 <code class="option">-u</code> option, as chrooting a process
142                 running as root doesn't enhance security on most
143                 systems; the way <code class="function">chroot()</code> is
144                 defined allows a process with root privileges to
145                 escape a chroot jail.
146             </p>
147 </div>
148 </dd>
149 <dt><span class="term">-u <em class="replaceable"><code>user</code></em></span></dt>
150 <dd><p>
151                 <code class="function">setuid()</code> to <em class="replaceable"><code>user</code></em> after completing
152                 privileged operations, such as creating sockets that
153                 listen on privileged ports.
154           </p></dd>
155 <dt><span class="term">-v</span></dt>
156 <dd><p>
157                 Report the version number and exit.
158           </p></dd>
159 </dl></div>
160 </div>
161 <div class="refsect1" lang="en">
162 <a name="id2549939"></a><h2>FILES</h2>
163 <div class="variablelist"><dl>
164 <dt><span class="term"><code class="filename">/etc/resolv.conf</code></span></dt>
165 <dd><p>
166                 The default configuration file.
167           </p></dd>
168 <dt><span class="term"><code class="filename">/var/run/lwresd.pid</code></span></dt>
169 <dd><p>
170                 The default process-id file.
171           </p></dd>
172 </dl></div>
173 </div>
174 <div class="refsect1" lang="en">
175 <a name="id2549978"></a><h2>SEE ALSO</h2>
176 <p>
177         <span class="citerefentry"><span class="refentrytitle">named</span>(8)</span>,
178         <span class="citerefentry"><span class="refentrytitle">lwres</span>(3)</span>,
179         <span class="citerefentry"><span class="refentrytitle">resolver</span>(5)</span>.
180     </p>
181 </div>
182 <div class="refsect1" lang="en">
183 <a name="id2550017"></a><h2>AUTHOR</h2>
184 <p>
185         <span class="corpauthor">Internet Systems Consortium</span>
186     </p>
187 </div>
188 </div></body>
189 </html>