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10139N/A<
tr><
th colspan="3" align="center"><
span class="application">lwresd</
span></
th></
tr>
10139N/A<
th width="60%" align="center">Manual pages</
th>
10139N/A <
span class="application">lwresd</
span>
10139N/A — lightweight resolver daemon
10139N/A <
code class="command">lwresd</
code>
10139N/A [<
code class="option">-c <
em class="replaceable"><
code>config-file</
code></
em></
code>]
10139N/A [<
code class="option">-C <
em class="replaceable"><
code>config-file</
code></
em></
code>]
10139N/A [<
code class="option">-d <
em class="replaceable"><
code>debug-level</
code></
em></
code>]
10139N/A [<
code class="option">-f</
code>]
10139N/A [<
code class="option">-g</
code>]
10139N/A [<
code class="option">-i <
em class="replaceable"><
code>pid-file</
code></
em></
code>]
10139N/A [<
code class="option">-m <
em class="replaceable"><
code>flag</
code></
em></
code>]
10139N/A [<
code class="option">-n <
em class="replaceable"><
code>#cpus</
code></
em></
code>]
10139N/A [<
code class="option">-P <
em class="replaceable"><
code>port</
code></
em></
code>]
10139N/A [<
code class="option">-p <
em class="replaceable"><
code>port</
code></
em></
code>]
10139N/A [<
code class="option">-s</
code>]
10139N/A [<
code class="option">-t <
em class="replaceable"><
code>directory</
code></
em></
code>]
19064N/A [<
code class="option">-u <
em class="replaceable"><
code>user</
code></
em></
code>]
10990N/A [<
code class="option">-v</
code>]
19064N/A [<
code class="option">-4</
code>]
10139N/A [<
code class="option">-6</
code>]
10139N/A<
a name="id-1.14.15.7"></
a><
h2>DESCRIPTION</
h2>
10139N/A <
p><
span class="command"><
strong>lwresd</
strong></
span>
10139N/A is the daemon providing name lookup
10139N/A services to clients that use the BIND 9 lightweight resolver
10139N/A library. It is essentially a stripped-down, caching-only name
10139N/A server that answers queries using the BIND 9 lightweight
10139N/A resolver protocol rather than the DNS protocol.
10139N/A <
p><
span class="command"><
strong>lwresd</
strong></
span>
10139N/A listens for resolver queries on a
10139N/A UDP port on the IPv4 loopback interface, 127.0.0.1. This
10139N/A means that <
span class="command"><
strong>lwresd</
strong></
span> can only be used by
10139N/A processes running on the local machine. By default, UDP port
10139N/A number 921 is used for lightweight resolver requests and
19064N/A Incoming lightweight resolver requests are decoded by the
19064N/A server which then resolves them using the DNS protocol. When
18636N/A the DNS lookup completes, <
span class="command"><
strong>lwresd</
strong></
span> encodes
18180N/A the answers in the lightweight resolver format and returns
18636N/A them to the client that made the request.
17548N/A <
code class="option">nameserver</
code> entries, <
span class="command"><
strong>lwresd</
strong></
span>
17548N/A sends recursive DNS queries to those servers. This is similar
16311N/A to the use of forwarders in a caching name server. If no
16311N/A <
code class="option">nameserver</
code> entries are present, or if
15703N/A forwarding fails, <
span class="command"><
strong>lwresd</
strong></
span> resolves the
15703N/A queries autonomously starting at the root name servers, using
15236N/A a built-in list of root server hints.
13614N/A<
a name="id-1.14.15.8"></
a><
h2>OPTIONS</
h2>
12004N/A <
div class="variablelist"><
dl class="variablelist">
12004N/A<
dt><
span class="term">-4</
span></
dt>
11046N/A Use IPv4 only even if the host machine is capable of IPv6.
11046N/A <
code class="option">-4</
code> and <
code class="option">-6</
code> are mutually
10392N/A<
dt><
span class="term">-6</
span></
dt>
10139N/A Use IPv6 only even if the host machine is capable of IPv4.
10139N/A <
code class="option">-4</
code> and <
code class="option">-6</
code> are mutually
10139N/A<
dt><
span class="term">-c <
em class="replaceable"><
code>config-file</
code></
em></
span></
dt>
10139N/A Use <
em class="replaceable"><
code>config-file</
code></
em> as the
10139N/A configuration file instead of the default,
10139N/A <
code class="option">-c</
code> can not be used with <
code class="option">-C</
code>.
10139N/A<
dt><
span class="term">-C <
em class="replaceable"><
code>config-file</
code></
em></
span></
dt>
10139N/A Use <
em class="replaceable"><
code>config-file</
code></
em> as the
10139N/A configuration file instead of the default,
10139N/A <
code class="option">-C</
code> can not be used with <
code class="option">-c</
code>.
10139N/A<
dt><
span class="term">-d <
em class="replaceable"><
code>debug-level</
code></
em></
span></
dt>
10139N/A Set the daemon's debug level to <
em class="replaceable"><
code>debug-level</
code></
em>.
10139N/A Debugging traces from <
span class="command"><
strong>lwresd</
strong></
span> become
10139N/A more verbose as the debug level increases.
10139N/A<
dt><
span class="term">-f</
span></
dt>
10139N/A Run the server in the foreground (
i.e. do not daemonize).
10139N/A<
dt><
span class="term">-g</
span></
dt>
10139N/A Run the server in the foreground and force all logging
10139N/A to <
code class="filename">stderr</
code>.
10139N/A<
dt><
span class="term">-i <
em class="replaceable"><
code>pid-file</
code></
em></
span></
dt>
10139N/A Use <
em class="replaceable"><
code>pid-file</
code></
em> as the
10139N/A PID file instead of the default,
10139N/A<
dt><
span class="term">-m <
em class="replaceable"><
code>flag</
code></
em></
span></
dt>
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>.
<
dt><
span class="term">-n <
em class="replaceable"><
code>#cpus</
code></
em></
span></
dt>
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.
<
dt><
span class="term">-P <
em class="replaceable"><
code>port</
code></
em></
span></
dt>
Listen for lightweight resolver queries on port
<
em class="replaceable"><
code>port</
code></
em>. If
not specified, the default is port 921.
<
dt><
span class="term">-p <
em class="replaceable"><
code>port</
code></
em></
span></
dt>
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
<
dt><
span class="term">-s</
span></
dt>
Write memory usage statistics to <
code class="filename">stdout</
code>
<
div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<
h3 class="title">Note</
h3>
This option is mainly of interest to BIND 9 developers
and may be removed or changed in a future release.
<
dt><
span class="term">-t <
em class="replaceable"><
code>directory</
code></
em></
span></
dt>
to <
em class="replaceable"><
code>directory</
code></
em> after
processing the command line arguments, but before
reading the configuration file.
<
div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
<
h3 class="title">Warning</
h3>
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
<
dt><
span class="term">-u <
em class="replaceable"><
code>user</
code></
em></
span></
dt>
to <
em class="replaceable"><
code>user</
code></
em> after completing
privileged operations, such as creating sockets that
listen on privileged ports.
<
dt><
span class="term">-v</
span></
dt>
Report the version number and exit.
<
a name="id-1.14.15.9"></
a><
h2>FILES</
h2>
<
div class="variablelist"><
dl class="variablelist">
<
dt><
span class="term"><
code class="filename">/
etc/
resolv.conf</
code></
span></
dt>
The default configuration file.
<
dt><
span class="term"><
code class="filename">/
var/
run/
lwresd.pid</
code></
span></
dt>
The default process-id file.
<
a name="id-1.14.15.10"></
a><
h2>SEE ALSO</
h2>
<
p><
span class="citerefentry">
<
span class="refentrytitle">named</
span>(8)
<
span class="citerefentry">
<
span class="refentrytitle">lwres</
span>(3)
<
span class="citerefentry">
<
span class="refentrytitle">resolver</
span>(5)
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