<?xml version="1.0"?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" lang="en"><head><title>Twisted Documentation: Creating and working with a names (DNS) server</title><link href="../howto/stylesheet.css" type="text/css" rel="stylesheet" /></head><body bgcolor="white"><h1 class="title">Creating and working with a names (DNS) server</h1><div class="toc"><ol><ul><li><a href="#auto0">Creating a non-authoritative server</a></li><li><a href="#auto1">Creating an authoritative server</a></li></ul></ol></div><div class="content"><span></span><p>A Names server can be perform three basic operations: <ul><li>act as a recursive server, forwarding queries to other servers</li><li>perform local caching of recursively discovered records</li><li>act as the authoritative server for a domain</li></ul><h3>Creating a non-authoritative server<a name="auto0"></a></h3> The first two of these are easy, and you can create a server that performs them with the command <code class="shell">mktap dns --recursive --cache</code>, or launch <code class="shell">tkmktap</code> and configure a dns server with it. The result should be a file named <code>dns.tap</code>. Now switch to a superuser account (if required by your platform to bind to port 53) and run <code class="shell">twistd -f dns.tap</code>. The Application will run and bind to port 53. Try performing a lookup with it, <code class="shell">dig twistedmatrix.com @127.0.0.1</code>. </p><h3>Creating an authoritative server<a name="auto1"></a></h3><p>To act as the authority for a domain, two things are necessary: the address of the machine on which the domain name server will run must be registered as a nameserver for the domain; and the domain name server must be configured to act as the authority. The first requirement is beyond the scope of this howto and will not be covered. </p><p>To configure Names to act as the authority for <code>example-domain.com</code>, we first create a zone file for this domain.</p><div class="py-listing"><pre> <span class="py-src-variable">zone</span> <span class="py-src-op">=</span> <span class="py-src-op">[</span><span class="py-src-nl"> </span> <span class="py-src-variable">SOA</span><span class="py-src-op">(</span><span class="py-src-nl"> </span> <span class="py-src-comment"># For whom we are the authority</span><span class="py-src-nl"> </span> <span class="py-src-string">'example-domain.com'</span><span class="py-src-op">,</span><span class="py-src-nl"> </span><span class="py-src-nl"> </span> <span class="py-src-comment"># This nameserver's name</span><span class="py-src-nl"> </span> <span class="py-src-variable">mname</span> <span class="py-src-op">=</span> <span class="py-src-string">"ns1.example-domain.com"</span><span class="py-src-op">,</span><span class="py-src-nl"> </span><span class="py-src-nl"> </span> <span class="py-src-comment"># Mailbox of individual who handles this</span><span class="py-src-nl"> </span> <span class="py-src-variable">rname</span> <span class="py-src-op">=</span> <span class="py-src-string">"root.example-domain.com"</span><span class="py-src-op">,</span><span class="py-src-nl"> </span><span class="py-src-nl"> </span> <span class="py-src-comment"># Unique serial identifying this SOA data</span><span class="py-src-nl"> </span> <span class="py-src-variable">serial</span> <span class="py-src-op">=</span> <span class="py-src-number">2003010601</span><span class="py-src-op">,</span><span class="py-src-nl"> </span><span class="py-src-nl"> </span> <span class="py-src-comment"># Time interval before zone should be refreshed</span><span class="py-src-nl"> </span> <span class="py-src-variable">refresh</span> <span class="py-src-op">=</span> <span class="py-src-string">"1H"</span><span class="py-src-op">,</span><span class="py-src-nl"> </span><span class="py-src-nl"> </span> <span class="py-src-comment"># Interval before failed refresh should be retried</span><span class="py-src-nl"> </span> <span class="py-src-variable">retry</span> <span class="py-src-op">=</span> <span class="py-src-string">"1H"</span><span class="py-src-op">,</span><span class="py-src-nl"> </span><span class="py-src-nl"> </span> <span class="py-src-comment"># Upper limit on time interval before expiry</span><span class="py-src-nl"> </span> <span class="py-src-variable">expire</span> <span class="py-src-op">=</span> <span class="py-src-string">"1H"</span><span class="py-src-op">,</span><span class="py-src-nl"> </span><span class="py-src-nl"> </span> <span class="py-src-comment"># Minimum TTL</span><span class="py-src-nl"> </span> <span class="py-src-variable">minimum</span> <span class="py-src-op">=</span> <span class="py-src-string">"1H"</span><span class="py-src-nl"> </span> <span class="py-src-op">)</span><span class="py-src-op">,</span><span class="py-src-nl"> </span><span class="py-src-nl"> </span> <span class="py-src-variable">A</span><span class="py-src-op">(</span><span class="py-src-string">'example-domain.com'</span><span class="py-src-op">,</span> <span class="py-src-string">'127.0.0.1'</span><span class="py-src-op">)</span><span class="py-src-op">,</span><span class="py-src-nl"> </span> <span class="py-src-variable">NS</span><span class="py-src-op">(</span><span class="py-src-string">'ns1.example-domain.com'</span><span class="py-src-op">,</span> <span class="py-src-string">'example-domain.com'</span><span class="py-src-op">)</span><span class="py-src-op">,</span><span class="py-src-nl"> </span><span class="py-src-nl"> </span> <span class="py-src-variable">CNAME</span><span class="py-src-op">(</span><span class="py-src-string">'www.example-domain.com'</span><span class="py-src-op">,</span> <span class="py-src-string">'example-domain.com'</span><span class="py-src-op">)</span><span class="py-src-op">,</span><span class="py-src-nl"> </span> <span class="py-src-variable">CNAME</span><span class="py-src-op">(</span><span class="py-src-string">'ftp.example-domain.com'</span><span class="py-src-op">,</span> <span class="py-src-string">'example-domain.com'</span><span class="py-src-op">)</span><span class="py-src-op">,</span><span class="py-src-nl"> </span><span class="py-src-nl"> </span> <span class="py-src-variable">MX</span><span class="py-src-op">(</span><span class="py-src-string">'example-domain.com'</span><span class="py-src-op">,</span> <span class="py-src-number">0</span><span class="py-src-op">,</span> <span class="py-src-string">'mail.example-domain.com'</span><span class="py-src-op">)</span><span class="py-src-op">,</span><span class="py-src-nl"> </span> <span class="py-src-variable">A</span><span class="py-src-op">(</span><span class="py-src-string">'mail.example-domain.com'</span><span class="py-src-op">,</span> <span class="py-src-string">'123.0.16.43'</span><span class="py-src-op">)</span><span class="py-src-nl"> </span><span class="py-src-op">]</span><span class="py-src-newline"> </span><span class="py-src-endmarker"></span></pre><div class="caption">Zone file - <a href="listings/names/example-domain.com"><span class="filename">listings/names/example-domain.com</span></a></div></div><p>Next, run the command <code class="shell">mktap dns --pyzone example-domain.com</code>, and then (as above) <code class="shell">twistd -f dns.tap</code>. Now try querying the domain locally (again, with dig): <code class="shell">dig -t any example-domain.com @127.0.0.1</code>. </p><p>Names can also read a traditional, BIND-syntax zone file. Specify these with the <code>--bindzone</code> parameter. The $GENERATE and $INCLUDE directives are not yet supported. </p></div><p><a href="../howto/index.html">Index</a></p><span class="version">Version: 1.3.0</span></body></html>