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Name Server Configuration</title> <meta name="generator" content="DocBook XSL Stylesheets V1.71.1"> <link rel="start" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual"> <link rel="up" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual"> <link rel="prev" href="Bv9ARM.ch02.html" title="Chapter 2. BIND Resource Requirements"> <link rel="next" href="Bv9ARM.ch04.html" title="Chapter 4. Advanced DNS Features"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr><th colspan="3" align="center">Chapter 3. Name Server Configuration</th></tr> <tr> <td width="20%" align="left"> <a accesskey="p" href="Bv9ARM.ch02.html">Prev</a> </td> <th width="60%" align="center"> </th> <td width="20%" align="right"> <a accesskey="n" href="Bv9ARM.ch04.html">Next</a> </td> </tr> </table> <hr> </div> <div class="chapter" lang="en"> <div class="titlepage"><div><div><h2 class="title"> <a name="Bv9ARM.ch03"></a>Chapter 3. Name Server Configuration</h2></div></div></div> <div class="toc"> <p><b>Table of Contents</b></p> <dl> <dt><span class="sect1"><a href="Bv9ARM.ch03.html#sample_configuration">Sample Configurations</a></span></dt> <dd><dl> <dt><span class="sect2"><a href="Bv9ARM.ch03.html#id2567771">A Caching-only Name Server</a></span></dt> <dt><span class="sect2"><a href="Bv9ARM.ch03.html#id2567992">An Authoritative-only Name Server</a></span></dt> </dl></dd> <dt><span class="sect1"><a href="Bv9ARM.ch03.html#id2568014">Load Balancing</a></span></dt> <dt><span class="sect1"><a href="Bv9ARM.ch03.html#id2568369">Name Server Operations</a></span></dt> <dd><dl> <dt><span class="sect2"><a href="Bv9ARM.ch03.html#id2568374">Tools for Use With the Name Server Daemon</a></span></dt> <dt><span class="sect2"><a href="Bv9ARM.ch03.html#id2570421">Signals</a></span></dt> </dl></dd> </dl> </div> <p> In this chapter we provide some suggested configurations along with guidelines for their use. We suggest reasonable values for certain option settings. </p> <div class="sect1" lang="en"> <div class="titlepage"><div><div><h2 class="title" style="clear: both"> <a name="sample_configuration"></a>Sample Configurations</h2></div></div></div> <div class="sect2" lang="en"> <div class="titlepage"><div><div><h3 class="title"> <a name="id2567771"></a>A Caching-only Name Server</h3></div></div></div> <p> The following sample configuration is appropriate for a caching-only name server for use by clients internal to a corporation. All queries from outside clients are refused using the <span><strong class="command">allow-query</strong></span> option. Alternatively, the same effect could be achieved using suitable firewall rules. </p> <pre class="programlisting"> // Two corporate subnets we wish to allow queries from. acl corpnets { 192.168.4.0/24; 192.168.7.0/24; }; options { // Working directory directory "/etc/namedb"; allow-query { corpnets; }; }; // Provide a reverse mapping for the loopback // address 127.0.0.1 zone "0.0.127.in-addr.arpa" { type master; file "localhost.rev"; notify no; }; </pre> </div> <div class="sect2" lang="en"> <div class="titlepage"><div><div><h3 class="title"> <a name="id2567992"></a>An Authoritative-only Name Server</h3></div></div></div> <p> This sample configuration is for an authoritative-only server that is the master server for "<code class="filename">example.com</code>" and a slave for the subdomain "<code class="filename">eng.example.com</code>". </p> <pre class="programlisting"> options { // Working directory directory "/etc/namedb"; // Do not allow access to cache allow-query-cache { none; }; // This is the default allow-query { any; }; // Do not provide recursive service recursion no; }; // Provide a reverse mapping for the loopback // address 127.0.0.1 zone "0.0.127.in-addr.arpa" { type master; file "localhost.rev"; notify no; }; // We are the master server for example.com zone "example.com" { type master; file "example.com.db"; // IP addresses of slave servers allowed to // transfer example.com allow-transfer { 192.168.4.14; 192.168.5.53; }; }; // 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="id2568014"></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> sub-statement 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="id2568369"></a>Name Server Operations</h2></div></div></div> <div class="sect2" lang="en"> <div class="titlepage"><div><div><h3 class="title"> <a name="id2568374"></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 <span><strong class="command">dig</strong></span> 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>sign <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> Fetch all DNSSEC keys for the given zone from the key directory (see <span><strong class="command">key-directory</strong></span> in <a href="Bv9ARM.ch06.html#options" title="options Statement Definition and Usage">the section called “<span><strong class="command">options</strong></span> Statement Definition and Usage”</a>). If they are within their publication period, merge them into the zone's DNSKEY RRset. If the DNSKEY RRset is changed, then the zone is automatically re-signed with the new key set. </p> <p> This command requires that the <span><strong class="command">auto-dnssec</strong></span> zone option be set to <code class="literal">allow</code> or <code class="literal">maintain</code>, and also requires the zone to be configured to allow dynamic DNS. See <a href="Bv9ARM.ch06.html#dynamic_update_policies" title="Dynamic Update Policies">the section called “Dynamic Update Policies”</a> for more details. </p> </dd> <dt><span class="term"><strong class="userinput"><code>loadkeys <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> Fetch all DNSSEC keys for the given zone from the key directory (see <span><strong class="command">key-directory</strong></span> in <a href="Bv9ARM.ch06.html#options" title="options Statement Definition and Usage">the section called “<span><strong class="command">options</strong></span> Statement Definition and Usage”</a>). If they are within their publication period, merge them into the zone's DNSKEY RRset. Unlike <span><strong class="command">rndc sign</strong></span>, however, the zone is not immediately re-signed by the new keys, but is allowed to incrementally re-sign over time. </p> <p> This command requires that the <span><strong class="command">auto-dnssec</strong></span> zone option be set to <code class="literal">maintain</code>, and also requires the zone to be configured to allow dynamic DNS. See <a href="Bv9ARM.ch06.html#dynamic_update_policies" title="Dynamic Update Policies">the section called “Dynamic Update Policies”</a> for more details. </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>secroots [<span class="optional"><em class="replaceable"><code>view ...</code></em></span>]</code></strong></span></dt> <dd><p> Dump the server's security roots to the secroots file for the specified views. If no view is specified, security roots for 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 <code class="option">-p</code> is specified <span><strong class="command">named</strong></span>'s process id is returned. This allows an external process to determine when <span><strong class="command">named</strong></span> 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 <code class="option">-p</code> is specified <span><strong class="command">named</strong></span>'s process id is returned. This allows an external process to determine when <span><strong class="command">named</strong></span> 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 <span><strong class="command">named</strong></span> 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> <dt><span class="term"><strong class="userinput"><code>tsig-list</code></strong></span></dt> <dd><p> List the names of all TSIG keys currently configured for use by <span><strong class="command">named</strong></span> in each view. The list both statically configured keys and dynamic TKEY-negotiated keys. </p></dd> <dt><span class="term"><strong class="userinput"><code>tsig-delete</code></strong> <em class="replaceable"><code>keyname</code></em> [<span class="optional"><em class="replaceable"><code>view</code></em></span>]</span></dt> <dd><p> Delete a given TKEY-negotated key from the server. (This does not apply to statically configured TSIG keys.) </p></dd> <dt><span class="term"><strong class="userinput"><code>addzone <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>] <em class="replaceable"><code>configuration</code></em> </code></strong></span></dt> <dd> <p> Add a zone while the server is running. This command requires the <span><strong class="command">allow-new-zones</strong></span> option to be set to <strong class="userinput"><code>yes</code></strong>. The <em class="replaceable"><code>configuration</code></em> string specified on the command line is the zone configuration text that would ordinarily be placed in <code class="filename">named.conf</code>. </p> <p> The configuration is saved in a file called <code class="filename"><em class="replaceable"><code>hash</code></em>.nzf</code>, where <em class="replaceable"><code>hash</code></em> is a cryptographic hash generated from the name of the view. When <span><strong class="command">named</strong></span> is restarted, the file will be loaded into the view configuration, so that zones that were added can persist after a restart. </p> <p> This sample <span><strong class="command">addzone</strong></span> command would add the zone <code class="literal">example.com</code> to the default view: </p> <p> <code class="prompt">$ </code><strong class="userinput"><code>rndc addzone example.com '{ type master; file "example.com.db"; };'</code></strong> </p> <p> (Note the brackets and semi-colon around the zone configuration text.) </p> </dd> <dt><span class="term"><strong class="userinput"><code>delzone <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> Delete a zone while the server is running. Only zones that were originally added via <span><strong class="command">rndc addzone</strong></span> can be deleted in this matter. </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 “<span><strong class="command">controls</strong></span> Statement Definition and Usage”</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 <code class="filename">named.conf</code>. 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="id2570421"></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> </div> <div class="navfooter"> <hr> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"> <a accesskey="p" href="Bv9ARM.ch02.html">Prev</a> </td> <td width="20%" align="center"> </td> <td width="40%" align="right"> <a accesskey="n" href="Bv9ARM.ch04.html">Next</a> </td> </tr> <tr> <td width="40%" align="left" valign="top">Chapter 2. <acronym class="acronym">BIND</acronym> Resource Requirements </td> <td width="20%" align="center"><a accesskey="h" href="Bv9ARM.html">Home</a></td> <td width="40%" align="right" valign="top"> Chapter 4. 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