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5 - Copyright (C) 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
6 - Copyright (C) 2000, 2001 Internet Software Consortium.
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15 - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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21 <!-- $Id: lwresd.docbook,v 1.7.18.5 2007/01/29 23:57:20 marka Exp $ -->
24 <date>June 30, 2000</date>
28 <refentrytitle><application>lwresd</application></refentrytitle>
29 <manvolnum>8</manvolnum>
30 <refmiscinfo>BIND9</refmiscinfo>
34 <refname><application>lwresd</application></refname>
35 <refpurpose>lightweight resolver daemon</refpurpose>
43 <holder>Internet Systems Consortium, Inc. ("ISC")</holder>
48 <holder>Internet Software Consortium.</holder>
54 <command>lwresd</command>
55 <arg><option>-C <replaceable class="parameter">config-file</replaceable></option></arg>
56 <arg><option>-d <replaceable class="parameter">debug-level</replaceable></option></arg>
57 <arg><option>-f</option></arg>
58 <arg><option>-g</option></arg>
59 <arg><option>-i <replaceable class="parameter">pid-file</replaceable></option></arg>
60 <arg><option>-n <replaceable class="parameter">#cpus</replaceable></option></arg>
61 <arg><option>-P <replaceable class="parameter">port</replaceable></option></arg>
62 <arg><option>-p <replaceable class="parameter">port</replaceable></option></arg>
63 <arg><option>-s</option></arg>
64 <arg><option>-t <replaceable class="parameter">directory</replaceable></option></arg>
65 <arg><option>-u <replaceable class="parameter">user</replaceable></option></arg>
66 <arg><option>-v</option></arg>
71 <title>DESCRIPTION</title>
73 <para><command>lwresd</command>
74 is the daemon providing name lookup
75 services to clients that use the BIND 9 lightweight resolver
76 library. It is essentially a stripped-down, caching-only name
77 server that answers queries using the BIND 9 lightweight
78 resolver protocol rather than the DNS protocol.
81 <para><command>lwresd</command>
82 listens for resolver queries on a
83 UDP port on the IPv4 loopback interface, 127.0.0.1. This
84 means that <command>lwresd</command> can only be used by
85 processes running on the local machine. By default UDP port
86 number 921 is used for lightweight resolver requests and
90 Incoming lightweight resolver requests are decoded by the
91 server which then resolves them using the DNS protocol. When
92 the DNS lookup completes, <command>lwresd</command> encodes
93 the answers in the lightweight resolver format and returns
94 them to the client that made the request.
97 If <filename>/etc/resolv.conf</filename> contains any
98 <option>nameserver</option> entries, <command>lwresd</command>
99 sends recursive DNS queries to those servers. This is similar
100 to the use of forwarders in a caching name server. If no
101 <option>nameserver</option> entries are present, or if
102 forwarding fails, <command>lwresd</command> resolves the
103 queries autonomously starting at the root name servers, using
104 a built-in list of root server hints.
109 <title>OPTIONS</title>
113 <term>-C <replaceable class="parameter">config-file</replaceable></term>
116 Use <replaceable class="parameter">config-file</replaceable> as the
117 configuration file instead of the default,
118 <filename>/etc/resolv.conf</filename>.
124 <term>-d <replaceable class="parameter">debug-level</replaceable></term>
127 Set the daemon's debug level to <replaceable class="parameter">debug-level</replaceable>.
128 Debugging traces from <command>lwresd</command> become
129 more verbose as the debug level increases.
138 Run the server in the foreground (i.e. do not daemonize).
147 Run the server in the foreground and force all logging
148 to <filename>stderr</filename>.
154 <term>-n <replaceable class="parameter">#cpus</replaceable></term>
157 Create <replaceable class="parameter">#cpus</replaceable> worker threads
158 to take advantage of multiple CPUs. If not specified,
159 <command>lwresd</command> will try to determine the
160 number of CPUs present and create one thread per CPU.
161 If it is unable to determine the number of CPUs, a
162 single worker thread will be created.
168 <term>-P <replaceable class="parameter">port</replaceable></term>
171 Listen for lightweight resolver queries on port
172 <replaceable class="parameter">port</replaceable>. If
173 not specified, the default is port 921.
179 <term>-p <replaceable class="parameter">port</replaceable></term>
182 Send DNS lookups to port <replaceable class="parameter">port</replaceable>. If not
183 specified, the default is port 53. This provides a
184 way of testing the lightweight resolver daemon with a
185 name server that listens for queries on a non-standard
195 Write memory usage statistics to <filename>stdout</filename>
200 This option is mainly of interest to BIND 9 developers
201 and may be removed or changed in a future release.
208 <term>-t <replaceable class="parameter">directory</replaceable></term>
210 <para><function>chroot()</function>
211 to <replaceable class="parameter">directory</replaceable> after
212 processing the command line arguments, but before
213 reading the configuration file.
217 This option should be used in conjunction with the
218 <option>-u</option> option, as chrooting a process
219 running as root doesn't enhance security on most
220 systems; the way <function>chroot()</function> is
221 defined allows a process with root privileges to
222 escape a chroot jail.
229 <term>-u <replaceable class="parameter">user</replaceable></term>
231 <para><function>setuid()</function>
232 to <replaceable class="parameter">user</replaceable> after completing
233 privileged operations, such as creating sockets that
234 listen on privileged ports.
243 Report the version number and exit.
258 <term><filename>/etc/resolv.conf</filename></term>
261 The default configuration file.
267 <term><filename>/var/run/lwresd.pid</filename></term>
270 The default process-id file.
280 <title>SEE ALSO</title>
282 <refentrytitle>named</refentrytitle><manvolnum>8</manvolnum>
285 <refentrytitle>lwres</refentrytitle><manvolnum>3</manvolnum>
288 <refentrytitle>resolver</refentrytitle><manvolnum>5</manvolnum>
294 <title>AUTHOR</title>
295 <para><corpauthor>Internet Systems Consortium</corpauthor>