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acronym> 9 Lightweight Resolver</
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acronym class="acronym">BIND</
acronym> 9 Lightweight Resolver</
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0N/A<
dt><
span class="section"><
a href="Bv9ARM.ch05.html#lightweight_resolver">The Lightweight Resolver Library</
a></
span></
dt>
58N/A<
dt><
span class="section"><
a href="Bv9ARM.ch05.html#lwresd">Running a Resolver Daemon</
a></
span></
dt>
99N/A<
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0N/A<
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h2 class="title" style="clear: both">
0N/A<
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a>The Lightweight Resolver Library</
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0N/A Traditionally applications have been linked with a stub resolver
0N/A library that sends recursive DNS queries to a local caching name
0N/A IPv6 once introduced new complexity into the resolution process,
0N/A such as following A6 chains and DNAME records, and simultaneous
0N/A lookup of IPv4 and IPv6 addresses. Though most of the complexity was
0N/A then removed, these are hard or impossible
58N/A to implement in a traditional stub resolver.
58N/A <
acronym class="acronym">BIND</
acronym> 9 therefore can also provide resolution
98N/A services to local clients
98N/A using a combination of a lightweight resolver library and a resolver
98N/A daemon process running on the local host. These communicate using
98N/A a simple UDP-based protocol, the "lightweight resolver protocol"
98N/A that is distinct from and simpler than the full DNS protocol.
98N/A<
div class="section">
98N/A<
div class="titlepage"><
div><
div><
h2 class="title" style="clear: both">
98N/A<
a name="lwresd"></
a>Running a Resolver Daemon</
h2></
div></
div></
div>
98N/A To use the lightweight resolver interface, the system must
98N/A run the resolver daemon <
span class="command"><
strong>lwresd</
strong></
span> or a
98N/A name server configured with a <
span class="command"><
strong>lwres</
strong></
span>
98N/A By default, applications using the lightweight resolver library will
98N/A UDP requests to the IPv4 loopback address (127.0.0.1) on port 921.
98N/A address can be overridden by <
span class="command"><
strong>lwserver</
strong></
span>
98N/A The daemon currently only looks in the DNS, but in the future
98N/A it may use other sources such as <
code class="filename">/
etc/
hosts</
code>,
0N/A The <
span class="command"><
strong>lwresd</
strong></
span> daemon is essentially a
0N/A caching-only name server that responds to requests using the
0N/A resolver protocol rather than the DNS protocol. Because it needs
0N/A to run on each host, it is designed to require no or minimal
0N/A Unless configured otherwise, it uses the name servers listed on
73N/A <
span class="command"><
strong>nameserver</
strong></
span> lines in <
code class="filename">/
etc/
resolv.conf</
code>
0N/A as forwarders, but is also capable of doing the resolution
0N/A The <
span class="command"><
strong>lwresd</
strong></
span> daemon may also be
0N/A <
code class="filename">
named.conf</
code> style configuration file,
0N/A be configured to act as a lightweight resolver daemon using the
0N/A <
span class="command"><
strong>lwres</
strong></
span> statement in <
code class="filename">
named.conf</
code>.
0N/A The number of client queries that the <
span class="command"><
strong>lwresd</
strong></
span>
0N/A daemon is able to serve can be set using the
0N/A <
code class="option">lwres-tasks</
code> and <
code class="option">lwres-clients</
code>
0N/A statements in the configuration.
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58N/A<
td width="40%" align="left" valign="top">Chapter�4.�Advanced DNS Features�</
td>
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a accesskey="h" href="Bv9ARM.html">Home</
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58N/A<
td width="40%" align="right" valign="top">�Chapter�6.�<
acronym class="acronym">BIND</
acronym> 9 Configuration Reference</
td>