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2d2eda71267231c2526be701fe655db125852c1ffielding<div class="chapter" lang="en">
2d2eda71267231c2526be701fe655db125852c1ffielding<div class="titlepage"><div><div><h2 class="title">
2d2eda71267231c2526be701fe655db125852c1ffielding<a name="Bv9ARM.ch03"></a>Chapter�3.�Name Server Configuration</h2></div></div></div>
2d2eda71267231c2526be701fe655db125852c1ffielding<div class="toc">
2d2eda71267231c2526be701fe655db125852c1ffielding<p><b>Table of Contents</b></p>
2d2eda71267231c2526be701fe655db125852c1ffielding<dl>
2d2eda71267231c2526be701fe655db125852c1ffielding<dt><span class="sect1"><a href="Bv9ARM.ch03.html#sample_configuration">Sample Configurations</a></span></dt>
2d2eda71267231c2526be701fe655db125852c1ffielding<dd><dl>
2d2eda71267231c2526be701fe655db125852c1ffielding<dt><span class="sect2"><a href="Bv9ARM.ch03.html#id2567894">A Caching-only Name Server</a></span></dt>
2d2eda71267231c2526be701fe655db125852c1ffielding<dt><span class="sect2"><a href="Bv9ARM.ch03.html#id2567910">An Authoritative-only Name Server</a></span></dt>
2d2eda71267231c2526be701fe655db125852c1ffielding</dl></dd>
2d2eda71267231c2526be701fe655db125852c1ffielding<dt><span class="sect1"><a href="Bv9ARM.ch03.html#id2568001">Load Balancing</a></span></dt>
2d2eda71267231c2526be701fe655db125852c1ffielding<dt><span class="sect1"><a href="Bv9ARM.ch03.html#id2568355">Name Server Operations</a></span></dt>
2d2eda71267231c2526be701fe655db125852c1ffielding<dd><dl>
2d2eda71267231c2526be701fe655db125852c1ffielding<dt><span class="sect2"><a href="Bv9ARM.ch03.html#id2568360">Tools for Use With the Name Server Daemon</a></span></dt>
2d2eda71267231c2526be701fe655db125852c1ffielding<dt><span class="sect2"><a href="Bv9ARM.ch03.html#id2570104">Signals</a></span></dt>
2d2eda71267231c2526be701fe655db125852c1ffielding</dl></dd>
2d2eda71267231c2526be701fe655db125852c1ffielding</dl>
2d2eda71267231c2526be701fe655db125852c1ffielding</div>
2d2eda71267231c2526be701fe655db125852c1ffielding<p>
2d2eda71267231c2526be701fe655db125852c1ffielding      In this section we provide some suggested configurations along
2d2eda71267231c2526be701fe655db125852c1ffielding      with guidelines for their use.  We suggest reasonable values for
2d2eda71267231c2526be701fe655db125852c1ffielding      certain option settings.
2d2eda71267231c2526be701fe655db125852c1ffielding    </p>
2d2eda71267231c2526be701fe655db125852c1ffielding<div class="sect1" lang="en">
2d2eda71267231c2526be701fe655db125852c1ffielding<div class="titlepage"><div><div><h2 class="title" style="clear: both">
2d2eda71267231c2526be701fe655db125852c1ffielding<a name="sample_configuration"></a>Sample Configurations</h2></div></div></div>
2d2eda71267231c2526be701fe655db125852c1ffielding<div class="sect2" lang="en">
2d2eda71267231c2526be701fe655db125852c1ffielding<div class="titlepage"><div><div><h3 class="title">
2d2eda71267231c2526be701fe655db125852c1ffielding<a name="id2567894"></a>A Caching-only Name Server</h3></div></div></div>
2d2eda71267231c2526be701fe655db125852c1ffielding<p>
2d2eda71267231c2526be701fe655db125852c1ffielding          The following sample configuration is appropriate for a caching-only
1acdb106aad7f32757afa07281b80e292229c3a8sf          name server for use by clients internal to a corporation.  All
2d2eda71267231c2526be701fe655db125852c1ffielding          queries
2d2eda71267231c2526be701fe655db125852c1ffielding          from outside clients are refused using the <span><strong class="command">allow-query</strong></span>
2d2eda71267231c2526be701fe655db125852c1ffielding          option.  Alternatively, the same effect could be achieved using
1acdb106aad7f32757afa07281b80e292229c3a8sf          suitable
1acdb106aad7f32757afa07281b80e292229c3a8sf          firewall rules.
1acdb106aad7f32757afa07281b80e292229c3a8sf        </p>
2d2eda71267231c2526be701fe655db125852c1ffielding<pre class="programlisting">
1acdb106aad7f32757afa07281b80e292229c3a8sf// Two corporate subnets we wish to allow queries from.
1acdb106aad7f32757afa07281b80e292229c3a8sfacl corpnets { 192.168.4.0/24; 192.168.7.0/24; };
1acdb106aad7f32757afa07281b80e292229c3a8sfoptions {
2d2eda71267231c2526be701fe655db125852c1ffielding     directory "/etc/namedb";           // Working directory
8b2f33c25de9a2e8ac689e633b4e8dfecdec31a3rjung     allow-query { corpnets; };
1acdb106aad7f32757afa07281b80e292229c3a8sf};
1acdb106aad7f32757afa07281b80e292229c3a8sf// Provide a reverse mapping for the loopback address 127.0.0.1
2d2eda71267231c2526be701fe655db125852c1ffieldingzone "0.0.127.in-addr.arpa" {
1acdb106aad7f32757afa07281b80e292229c3a8sf     type master;
1acdb106aad7f32757afa07281b80e292229c3a8sf     file "localhost.rev";
1acdb106aad7f32757afa07281b80e292229c3a8sf     notify no;
1acdb106aad7f32757afa07281b80e292229c3a8sf};
1acdb106aad7f32757afa07281b80e292229c3a8sf</pre>
1acdb106aad7f32757afa07281b80e292229c3a8sf</div>
1acdb106aad7f32757afa07281b80e292229c3a8sf<div class="sect2" lang="en">
1acdb106aad7f32757afa07281b80e292229c3a8sf<div class="titlepage"><div><div><h3 class="title">
1acdb106aad7f32757afa07281b80e292229c3a8sf<a name="id2567910"></a>An Authoritative-only Name Server</h3></div></div></div>
1acdb106aad7f32757afa07281b80e292229c3a8sf<p>
1acdb106aad7f32757afa07281b80e292229c3a8sf          This sample configuration is for an authoritative-only server
1acdb106aad7f32757afa07281b80e292229c3a8sf          that is the master server for "<code class="filename">example.com</code>"
1acdb106aad7f32757afa07281b80e292229c3a8sf          and a slave for the subdomain "<code class="filename">eng.example.com</code>".
1acdb106aad7f32757afa07281b80e292229c3a8sf        </p>
1acdb106aad7f32757afa07281b80e292229c3a8sf<pre class="programlisting">
1acdb106aad7f32757afa07281b80e292229c3a8sfoptions {
2d2eda71267231c2526be701fe655db125852c1ffielding     directory "/etc/namedb";           // Working directory
1acdb106aad7f32757afa07281b80e292229c3a8sf     allow-query-cache { none; };       // Do not allow access to cache
1acdb106aad7f32757afa07281b80e292229c3a8sf     allow-query { any; };              // This is the default
1acdb106aad7f32757afa07281b80e292229c3a8sf     recursion no;                      // Do not provide recursive service
2d2eda71267231c2526be701fe655db125852c1ffielding};
1acdb106aad7f32757afa07281b80e292229c3a8sf
1acdb106aad7f32757afa07281b80e292229c3a8sf// Provide a reverse mapping for the loopback address 127.0.0.1
2d2eda71267231c2526be701fe655db125852c1ffieldingzone "0.0.127.in-addr.arpa" {
1acdb106aad7f32757afa07281b80e292229c3a8sf     type master;
1acdb106aad7f32757afa07281b80e292229c3a8sf     file "localhost.rev";
1acdb106aad7f32757afa07281b80e292229c3a8sf     notify no;
1acdb106aad7f32757afa07281b80e292229c3a8sf};
1acdb106aad7f32757afa07281b80e292229c3a8sf// We are the master server for example.com
2d2eda71267231c2526be701fe655db125852c1ffieldingzone "example.com" {
1acdb106aad7f32757afa07281b80e292229c3a8sf     type master;
1acdb106aad7f32757afa07281b80e292229c3a8sf     file "example.com.db";
1acdb106aad7f32757afa07281b80e292229c3a8sf     // IP addresses of slave servers allowed to transfer example.com
2d2eda71267231c2526be701fe655db125852c1ffielding     allow-transfer {
1acdb106aad7f32757afa07281b80e292229c3a8sf          192.168.4.14;
2d2eda71267231c2526be701fe655db125852c1ffielding          192.168.5.53;
2d2eda71267231c2526be701fe655db125852c1ffielding     };
2d2eda71267231c2526be701fe655db125852c1ffielding};
// We are a slave server for eng.example.com
zone "eng.example.com" {
     type slave;
     file "eng.example.com.bk";
     // IP address of eng.example.com master server
     masters { 192.168.4.12; };
};
</pre>
</div>
</div>
<div class="sect1" lang="en">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="id2568001"></a>Load Balancing</h2></div></div></div>
<p>
        A primitive form of load balancing can be achieved in
        the <acronym class="acronym">DNS</acronym> by using multiple records
        (such as multiple A records) for one name.
      </p>
<p>
        For example, if you have three WWW servers with network addresses
        of 10.0.0.1, 10.0.0.2 and 10.0.0.3, a set of records such as the
        following means that clients will connect to each machine one third
        of the time:
      </p>
<div class="informaltable"><table border="1">
<colgroup>
<col>
<col>
<col>
<col>
<col>
</colgroup>
<tbody>
<tr>
<td>
                <p>
                  Name
                </p>
              </td>
<td>
                <p>
                  TTL
                </p>
              </td>
<td>
                <p>
                  CLASS
                </p>
              </td>
<td>
                <p>
                  TYPE
                </p>
              </td>
<td>
                <p>
                  Resource Record (RR) Data
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="literal">www</code>
                </p>
              </td>
<td>
                <p>
                  <code class="literal">600</code>
                </p>
              </td>
<td>
                <p>
                  <code class="literal">IN</code>
                </p>
              </td>
<td>
                <p>
                  <code class="literal">A</code>
                </p>
              </td>
<td>
                <p>
                  <code class="literal">10.0.0.1</code>
                </p>
              </td>
</tr>
<tr>
<td>
                <p></p>
              </td>
<td>
                <p>
                  <code class="literal">600</code>
                </p>
              </td>
<td>
                <p>
                  <code class="literal">IN</code>
                </p>
              </td>
<td>
                <p>
                  <code class="literal">A</code>
                </p>
              </td>
<td>
                <p>
                  <code class="literal">10.0.0.2</code>
                </p>
              </td>
</tr>
<tr>
<td>
                <p></p>
              </td>
<td>
                <p>
                  <code class="literal">600</code>
                </p>
              </td>
<td>
                <p>
                  <code class="literal">IN</code>
                </p>
              </td>
<td>
                <p>
                  <code class="literal">A</code>
                </p>
              </td>
<td>
                <p>
                  <code class="literal">10.0.0.3</code>
                </p>
              </td>
</tr>
</tbody>
</table></div>
<p>
        When a resolver queries for these records, <acronym class="acronym">BIND</acronym> will rotate
        them and respond to the query with the records in a different
        order.  In the example above, clients will randomly receive
        records in the order 1, 2, 3; 2, 3, 1; and 3, 1, 2. Most clients
        will use the first record returned and discard the rest.
      </p>
<p>
        For more detail on ordering responses, check the
        <span><strong class="command">rrset-order</strong></span> substatement in the
        <span><strong class="command">options</strong></span> statement, see
        <a href="Bv9ARM.ch06.html#rrset_ordering">RRset Ordering</a>.
      </p>
</div>
<div class="sect1" lang="en">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="id2568355"></a>Name Server Operations</h2></div></div></div>
<div class="sect2" lang="en">
<div class="titlepage"><div><div><h3 class="title">
<a name="id2568360"></a>Tools for Use With the Name Server Daemon</h3></div></div></div>
<p>
          This section describes several indispensable diagnostic,
          administrative and monitoring tools available to the system
          administrator for controlling and debugging the name server
          daemon.
        </p>
<div class="sect3" lang="en">
<div class="titlepage"><div><div><h4 class="title">
<a name="diagnostic_tools"></a>Diagnostic Tools</h4></div></div></div>
<p>
            The <span><strong class="command">dig</strong></span>, <span><strong class="command">host</strong></span>, and
            <span><strong class="command">nslookup</strong></span> programs are all command
            line tools
            for manually querying name servers.  They differ in style and
            output format.
          </p>
<div class="variablelist"><dl>
<dt><span class="term"><a name="dig"></a><span><strong class="command">dig</strong></span></span></dt>
<dd>
<p>
                  The domain information groper (<span><strong class="command">dig</strong></span>)
                  is the most versatile and complete of these lookup tools.
                  It has two modes: simple interactive
                  mode for a single query, and batch mode which executes a
                  query for
                  each in a list of several query lines. All query options are
                  accessible
                  from the command line.
                </p>
<div class="cmdsynopsis"><p><code class="command">dig</code>  [@<em class="replaceable"><code>server</code></em>]  <em class="replaceable"><code>domain</code></em>  [<em class="replaceable"><code>query-type</code></em>] [<em class="replaceable"><code>query-class</code></em>] [+<em class="replaceable"><code>query-option</code></em>] [-<em class="replaceable"><code>dig-option</code></em>] [%<em class="replaceable"><code>comment</code></em>]</p></div>
<p>
                  The usual simple use of dig will take the form
                </p>
<p>
                  <span><strong class="command">dig @server domain query-type query-class</strong></span>
                </p>
<p>
                  For more information and a list of available commands and
                  options, see the <span><strong class="command">dig</strong></span> man
                  page.
                </p>
</dd>
<dt><span class="term"><span><strong class="command">host</strong></span></span></dt>
<dd>
<p>
                  The <span><strong class="command">host</strong></span> utility emphasizes
                  simplicity
                  and ease of use.  By default, it converts
                  between host names and Internet addresses, but its
                  functionality
                  can be extended with the use of options.
                </p>
<div class="cmdsynopsis"><p><code class="command">host</code>  [-aCdlnrsTwv] [-c <em class="replaceable"><code>class</code></em>] [-N <em class="replaceable"><code>ndots</code></em>] [-t <em class="replaceable"><code>type</code></em>] [-W <em class="replaceable"><code>timeout</code></em>] [-R <em class="replaceable"><code>retries</code></em>] [-m <em class="replaceable"><code>flag</code></em>] [-4] [-6]  <em class="replaceable"><code>hostname</code></em>  [<em class="replaceable"><code>server</code></em>]</p></div>
<p>
                  For more information and a list of available commands and
                  options, see the <span><strong class="command">host</strong></span> man
                  page.
                </p>
</dd>
<dt><span class="term"><span><strong class="command">nslookup</strong></span></span></dt>
<dd>
<p><span><strong class="command">nslookup</strong></span>
                  has two modes: interactive and
                  non-interactive. Interactive mode allows the user to
                  query name servers for information about various
                  hosts and domains or to print a list of hosts in a
                  domain. Non-interactive mode is used to print just
                  the name and requested information for a host or
                  domain.
                </p>
<div class="cmdsynopsis"><p><code class="command">nslookup</code>  [-option...] [[<em class="replaceable"><code>host-to-find</code></em>] |  [- [server]]]</p></div>
<p>
                  Interactive mode is entered when no arguments are given (the
                  default name server will be used) or when the first argument
                  is a
                  hyphen (`-') and the second argument is the host name or
                  Internet address
                  of a name server.
                </p>
<p>
                  Non-interactive mode is used when the name or Internet
                  address
                  of the host to be looked up is given as the first argument.
                  The
                  optional second argument specifies the host name or address
                  of a name server.
                </p>
<p>
                  Due to its arcane user interface and frequently inconsistent
                  behavior, we do not recommend the use of <span><strong class="command">nslookup</strong></span>.
                  Use <span><strong class="command">dig</strong></span> instead.
                </p>
</dd>
</dl></div>
</div>
<div class="sect3" lang="en">
<div class="titlepage"><div><div><h4 class="title">
<a name="admin_tools"></a>Administrative Tools</h4></div></div></div>
<p>
            Administrative tools play an integral part in the management
            of a server.
          </p>
<div class="variablelist"><dl>
<dt>
<a name="named-checkconf"></a><span class="term"><span><strong class="command">named-checkconf</strong></span></span>
</dt>
<dd>
<p>
                  The <span><strong class="command">named-checkconf</strong></span> program
                  checks the syntax of a <code class="filename">named.conf</code> file.
                </p>
<div class="cmdsynopsis"><p><code class="command">named-checkconf</code>  [-jvz] [-t <em class="replaceable"><code>directory</code></em>] [<em class="replaceable"><code>filename</code></em>]</p></div>
</dd>
<dt>
<a name="named-checkzone"></a><span class="term"><span><strong class="command">named-checkzone</strong></span></span>
</dt>
<dd>
<p>
                  The <span><strong class="command">named-checkzone</strong></span> program
                  checks a master file for
                  syntax and consistency.
                </p>
<div class="cmdsynopsis"><p><code class="command">named-checkzone</code>  [-djqvD] [-c <em class="replaceable"><code>class</code></em>] [-o <em class="replaceable"><code>output</code></em>] [-t <em class="replaceable"><code>directory</code></em>] [-w <em class="replaceable"><code>directory</code></em>] [-k <em class="replaceable"><code>(ignore|warn|fail)</code></em>] [-n <em class="replaceable"><code>(ignore|warn|fail)</code></em>] [-W <em class="replaceable"><code>(ignore|warn)</code></em>]  <em class="replaceable"><code>zone</code></em>  [<em class="replaceable"><code>filename</code></em>]</p></div>
</dd>
<dt>
<a name="named-compilezone"></a><span class="term"><span><strong class="command">named-compilezone</strong></span></span>
</dt>
<dd><p>
                  Similar to <span><strong class="command">named-checkzone,</strong></span> but
                  it always dumps the zone content to a specified file
                  (typically in a different format).
                </p></dd>
<dt>
<a name="rndc"></a><span class="term"><span><strong class="command">rndc</strong></span></span>
</dt>
<dd>
<p>
                  The remote name daemon control
                  (<span><strong class="command">rndc</strong></span>) program allows the
                  system
                  administrator to control the operation of a name server.
                  Since <acronym class="acronym">BIND</acronym> 9.2, <span><strong class="command">rndc</strong></span>
                  supports all the commands of the BIND 8 <span><strong class="command">ndc</strong></span>
                  utility except <span><strong class="command">ndc start</strong></span> and
                  <span><strong class="command">ndc restart</strong></span>, which were also
                  not supported in <span><strong class="command">ndc</strong></span>'s
                  channel mode.
                  If you run <span><strong class="command">rndc</strong></span> without any
                  options
                  it will display a usage message as follows:
                </p>
<div class="cmdsynopsis"><p><code class="command">rndc</code>  [-c <em class="replaceable"><code>config</code></em>] [-s <em class="replaceable"><code>server</code></em>] [-p <em class="replaceable"><code>port</code></em>] [-y <em class="replaceable"><code>key</code></em>]  <em class="replaceable"><code>command</code></em>  [<em class="replaceable"><code>command</code></em>...]</p></div>
<p>The <span><strong class="command">command</strong></span>
                  is one of the following:
                </p>
<div class="variablelist"><dl>
<dt><span class="term"><strong class="userinput"><code>reload</code></strong></span></dt>
<dd><p>
                        Reload configuration file and zones.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>reload <em class="replaceable"><code>zone</code></em>
                        [<span class="optional"><em class="replaceable"><code>class</code></em>
           [<span class="optional"><em class="replaceable"><code>view</code></em></span>]</span>]</code></strong></span></dt>
<dd><p>
                        Reload the given zone.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>refresh <em class="replaceable"><code>zone</code></em>
                        [<span class="optional"><em class="replaceable"><code>class</code></em>
           [<span class="optional"><em class="replaceable"><code>view</code></em></span>]</span>]</code></strong></span></dt>
<dd><p>
                        Schedule zone maintenance for the given zone.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>retransfer <em class="replaceable"><code>zone</code></em>

                        [<span class="optional"><em class="replaceable"><code>class</code></em>
           [<span class="optional"><em class="replaceable"><code>view</code></em></span>]</span>]</code></strong></span></dt>
<dd><p>
                        Retransfer the given zone from the master.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>freeze
                        [<span class="optional"><em class="replaceable"><code>zone</code></em>
       [<span class="optional"><em class="replaceable"><code>class</code></em>
           [<span class="optional"><em class="replaceable"><code>view</code></em></span>]</span>]</span>]</code></strong></span></dt>
<dd><p>
                        Suspend updates to a dynamic zone.  If no zone is
                        specified,
                        then all zones are suspended.  This allows manual
                        edits to be made to a zone normally updated by dynamic
                        update.  It
                        also causes changes in the journal file to be synced
                        into the master
                        and the journal file to be removed.  All dynamic
                        update attempts will
                        be refused while the zone is frozen.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>thaw
                        [<span class="optional"><em class="replaceable"><code>zone</code></em>
       [<span class="optional"><em class="replaceable"><code>class</code></em>
           [<span class="optional"><em class="replaceable"><code>view</code></em></span>]</span>]</span>]</code></strong></span></dt>
<dd><p>
                        Enable updates to a frozen dynamic zone.  If no zone
                        is
                        specified, then all frozen zones are enabled.  This
                        causes
                        the server to reload the zone from disk, and
                        re-enables dynamic updates
                        after the load has completed.  After a zone is thawed,
                        dynamic updates
                        will no longer be refused.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>notify <em class="replaceable"><code>zone</code></em>
                        [<span class="optional"><em class="replaceable"><code>class</code></em>
           [<span class="optional"><em class="replaceable"><code>view</code></em></span>]</span>]</code></strong></span></dt>
<dd><p>
                        Resend NOTIFY messages for the zone.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>reconfig</code></strong></span></dt>
<dd><p>
                        Reload the configuration file and load new zones,
                        but do not reload existing zone files even if they
                        have changed.
                        This is faster than a full <span><strong class="command">reload</strong></span> when there
                        is a large number of zones because it avoids the need
                        to examine the
                        modification times of the zones files.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>stats</code></strong></span></dt>
<dd><p>
                        Write server statistics to the statistics file.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>querylog</code></strong></span></dt>
<dd><p>
                        Toggle query logging. Query logging can also be enabled
                        by explicitly directing the <span><strong class="command">queries</strong></span>
                        <span><strong class="command">category</strong></span> to a
                        <span><strong class="command">channel</strong></span> in the
                        <span><strong class="command">logging</strong></span> section of
                        <code class="filename">named.conf</code> or by specifying
                        <span><strong class="command">querylog yes;</strong></span> in the
                        <span><strong class="command">options</strong></span> section of
                        <code class="filename">named.conf</code>.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>dumpdb
                        [<span class="optional">-all|-cache|-zone</span>]
                        [<span class="optional"><em class="replaceable"><code>view ...</code></em></span>]</code></strong></span></dt>
<dd><p>
                        Dump the server's caches (default) and/or zones to
                        the
                        dump file for the specified views.  If no view is
                        specified, all
                        views are dumped.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>stop [<span class="optional">-p</span>]</code></strong></span></dt>
<dd><p>
                        Stop the server, making sure any recent changes
                        made through dynamic update or IXFR are first saved to
                        the master files of the updated zones.
                        If -p is specified named's process id is returned.
                        This allows an external process to determine when named
                        had completed stopping.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>halt [<span class="optional">-p</span>]</code></strong></span></dt>
<dd><p>
                        Stop the server immediately.  Recent changes
                        made through dynamic update or IXFR are not saved to
                        the master files, but will be rolled forward from the
                        journal files when the server is restarted.
                        If -p is specified named's process id is returned.
                        This allows an external process to determine when named
                        had completed halting.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>trace</code></strong></span></dt>
<dd><p>
                        Increment the servers debugging level by one.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>trace <em class="replaceable"><code>level</code></em></code></strong></span></dt>
<dd><p>
                        Sets the server's debugging level to an explicit
                        value.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>notrace</code></strong></span></dt>
<dd><p>
                        Sets the server's debugging level to 0.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>flush</code></strong></span></dt>
<dd><p>
                        Flushes the server's cache.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>flushname</code></strong> <em class="replaceable"><code>name</code></em></span></dt>
<dd><p>
                        Flushes the given name from the server's cache.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>status</code></strong></span></dt>
<dd><p>
                        Display status of the server.
                        Note that the number of zones includes the internal <span><strong class="command">bind/CH</strong></span> zone
                        and the default <span><strong class="command">/IN</strong></span>
                        hint zone if there is not an
                        explicit root zone configured.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>recursing</code></strong></span></dt>
<dd><p>
                        Dump the list of queries named is currently recursing
                        on.
                      </p></dd>
<dt><span class="term"><strong class="userinput"><code>validation
                        [<span class="optional">on|off</span>]
                        [<span class="optional"><em class="replaceable"><code>view ...</code></em></span>]
                    </code></strong></span></dt>
<dd><p>
                        Enable or disable DNSSEC validation.
                        Note <span><strong class="command">dnssec-enable</strong></span> also needs to be
                        set to <strong class="userinput"><code>yes</code></strong> to be effective.
                        It defaults to enabled.
                      </p></dd>
</dl></div>
<p>
                  A configuration file is required, since all
                  communication with the server is authenticated with
                  digital signatures that rely on a shared secret, and
                  there is no way to provide that secret other than with a
                  configuration file.  The default location for the
                  <span><strong class="command">rndc</strong></span> configuration file is
                  <code class="filename">/etc/rndc.conf</code>, but an
                  alternate
                  location can be specified with the <code class="option">-c</code>
                  option.  If the configuration file is not found,
                  <span><strong class="command">rndc</strong></span> will also look in
                  <code class="filename">/etc/rndc.key</code> (or whatever
                  <code class="varname">sysconfdir</code> was defined when
                  the <acronym class="acronym">BIND</acronym> build was
                  configured).
                  The <code class="filename">rndc.key</code> file is
                  generated by
                  running <span><strong class="command">rndc-confgen -a</strong></span> as
                  described in
                  <a href="Bv9ARM.ch06.html#controls_statement_definition_and_usage" title="controls Statement Definition and
          Usage">the section called &#8220;<span><strong class="command">controls</strong></span> Statement Definition and
          Usage&#8221;</a>.
                </p>
<p>
                  The format of the configuration file is similar to
                  that of <code class="filename">named.conf</code>, but
                  limited to
                  only four statements, the <span><strong class="command">options</strong></span>,
                  <span><strong class="command">key</strong></span>, <span><strong class="command">server</strong></span> and
                  <span><strong class="command">include</strong></span>
                  statements.  These statements are what associate the
                  secret keys to the servers with which they are meant to
                  be shared.  The order of statements is not
                  significant.
                </p>
<p>
                  The <span><strong class="command">options</strong></span> statement has
                  three clauses:
                  <span><strong class="command">default-server</strong></span>, <span><strong class="command">default-key</strong></span>,
                  and <span><strong class="command">default-port</strong></span>.
                  <span><strong class="command">default-server</strong></span> takes a
                  host name or address argument  and represents the server
                  that will
                  be contacted if no <code class="option">-s</code>
                  option is provided on the command line.
                  <span><strong class="command">default-key</strong></span> takes
                  the name of a key as its argument, as defined by a <span><strong class="command">key</strong></span> statement.
                  <span><strong class="command">default-port</strong></span> specifies the
                  port to which
                  <span><strong class="command">rndc</strong></span> should connect if no
                  port is given on the command line or in a
                  <span><strong class="command">server</strong></span> statement.
                </p>
<p>
                  The <span><strong class="command">key</strong></span> statement defines a
                  key to be used
                  by <span><strong class="command">rndc</strong></span> when authenticating
                  with
                  <span><strong class="command">named</strong></span>.  Its syntax is
                  identical to the
                  <span><strong class="command">key</strong></span> statement in named.conf.
                  The keyword <strong class="userinput"><code>key</code></strong> is
                  followed by a key name, which must be a valid
                  domain name, though it need not actually be hierarchical;
                  thus,
                  a string like "<strong class="userinput"><code>rndc_key</code></strong>" is a valid
                  name.
                  The <span><strong class="command">key</strong></span> statement has two
                  clauses:
                  <span><strong class="command">algorithm</strong></span> and <span><strong class="command">secret</strong></span>.
                  While the configuration parser will accept any string as the
                  argument
                  to algorithm, currently only the string "<strong class="userinput"><code>hmac-md5</code></strong>"
                  has any meaning.  The secret is a base-64 encoded string
                  as specified in RFC 3548.
                </p>
<p>
                  The <span><strong class="command">server</strong></span> statement
                  associates a key
                  defined using the <span><strong class="command">key</strong></span>
                  statement with a server.
                  The keyword <strong class="userinput"><code>server</code></strong> is followed by a
                  host name or address.  The <span><strong class="command">server</strong></span> statement
                  has two clauses: <span><strong class="command">key</strong></span> and <span><strong class="command">port</strong></span>.
                  The <span><strong class="command">key</strong></span> clause specifies the
                  name of the key
                  to be used when communicating with this server, and the
                  <span><strong class="command">port</strong></span> clause can be used to
                  specify the port <span><strong class="command">rndc</strong></span> should
                  connect
                  to on the server.
                </p>
<p>
                  A sample minimal configuration file is as follows:
                </p>
<pre class="programlisting">
key rndc_key {
     algorithm "hmac-md5";
     secret "c3Ryb25nIGVub3VnaCBmb3IgYSBtYW4gYnV0IG1hZGUgZm9yIGEgd29tYW4K";
};
options {
     default-server 127.0.0.1;
     default-key    rndc_key;
};
</pre>
<p>
                  This file, if installed as <code class="filename">/etc/rndc.conf</code>,
                  would allow the command:
                </p>
<p>
                  <code class="prompt">$ </code><strong class="userinput"><code>rndc reload</code></strong>
                </p>
<p>
                  to connect to 127.0.0.1 port 953 and cause the name server
                  to reload, if a name server on the local machine were
                  running with
                  following controls statements:
                </p>
<pre class="programlisting">
controls {
        inet 127.0.0.1 allow { localhost; } keys { rndc_key; };
};
</pre>
<p>
                  and it had an identical key statement for
                  <code class="literal">rndc_key</code>.
                </p>
<p>
                  Running the <span><strong class="command">rndc-confgen</strong></span>
                  program will
                  conveniently create a <code class="filename">rndc.conf</code>
                  file for you, and also display the
                  corresponding <span><strong class="command">controls</strong></span>
                  statement that you need to
                  add to <code class="filename">named.conf</code>.
                  Alternatively,
                  you can run <span><strong class="command">rndc-confgen -a</strong></span>
                  to set up
                  a <code class="filename">rndc.key</code> file and not
                  modify
                  <code class="filename">named.conf</code> at all.
                </p>
</dd>
</dl></div>
</div>
</div>
<div class="sect2" lang="en">
<div class="titlepage"><div><div><h3 class="title">
<a name="id2570104"></a>Signals</h3></div></div></div>
<p>
          Certain UNIX signals cause the name server to take specific
          actions, as described in the following table.  These signals can
          be sent using the <span><strong class="command">kill</strong></span> command.
        </p>
<div class="informaltable"><table border="1">
<colgroup>
<col>
<col>
</colgroup>
<tbody>
<tr>
<td>
                  <p><span><strong class="command">SIGHUP</strong></span></p>
                </td>
<td>
                  <p>
                    Causes the server to read <code class="filename">named.conf</code> and
                    reload the database.
                  </p>
                </td>
</tr>
<tr>
<td>
                  <p><span><strong class="command">SIGTERM</strong></span></p>
                </td>
<td>
                  <p>
                    Causes the server to clean up and exit.
                  </p>
                </td>
</tr>
<tr>
<td>
                  <p><span><strong class="command">SIGINT</strong></span></p>
                </td>
<td>
                  <p>
                    Causes the server to clean up and exit.
                  </p>
                </td>
</tr>
</tbody>
</table></div>
</div>
</div>
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