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<title>Twisted Documentation: Creating and working with a names (DNS) server</title>
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<h1 class="title">Creating and working with a names (DNS) server</h1>
<div class="toc"><ol><li><a href="#auto0">Creating a non-authoritative server</a></li><li><a href="#auto1">Creating an authoritative server</a></li></ol></div>
<div class="content">
<span/>
<p>A Names server can be perform three basic operations:</p>
<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>
<h2>Creating a non-authoritative server<a name="auto0"/></h2>
<p>
The first two of these are easy, and you can create a server that performs them
with the command <code class="shell">twistd -n dns --recursive --cache</code>.
You may wish to run this as root since it will try to bind to UDP port 53. Try
performing a lookup with it, <code class="shell">dig twistedmatrix.com
@127.0.0.1</code>.
</p>
<h2>Creating an authoritative server<a name="auto1"/></h2>
<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>
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</p><span class="py-src-variable">zone</span> = [
<span class="py-src-variable">SOA</span>(
<span class="py-src-comment"># For whom we are the authority</span>
<span class="py-src-string">'example-domain.com'</span>,
<span class="py-src-comment"># This nameserver's name</span>
<span class="py-src-variable">mname</span> = <span class="py-src-string">"ns1.example-domain.com"</span>,
<span class="py-src-comment"># Mailbox of individual who handles this</span>
<span class="py-src-variable">rname</span> = <span class="py-src-string">"root.example-domain.com"</span>,
<span class="py-src-comment"># Unique serial identifying this SOA data</span>
<span class="py-src-variable">serial</span> = <span class="py-src-number">2003010601</span>,
<span class="py-src-comment"># Time interval before zone should be refreshed</span>
<span class="py-src-variable">refresh</span> = <span class="py-src-string">"1H"</span>,
<span class="py-src-comment"># Interval before failed refresh should be retried</span>
<span class="py-src-variable">retry</span> = <span class="py-src-string">"1H"</span>,
<span class="py-src-comment"># Upper limit on time interval before expiry</span>
<span class="py-src-variable">expire</span> = <span class="py-src-string">"1H"</span>,
<span class="py-src-comment"># Minimum TTL</span>
<span class="py-src-variable">minimum</span> = <span class="py-src-string">"1H"</span>
),
<span class="py-src-variable">A</span>(<span class="py-src-string">'example-domain.com'</span>, <span class="py-src-string">'127.0.0.1'</span>),
<span class="py-src-variable">NS</span>(<span class="py-src-string">'example-domain.com'</span>, <span class="py-src-string">'ns1.example-domain.com'</span>),
<span class="py-src-variable">CNAME</span>(<span class="py-src-string">'www.example-domain.com'</span>, <span class="py-src-string">'example-domain.com'</span>),
<span class="py-src-variable">CNAME</span>(<span class="py-src-string">'ftp.example-domain.com'</span>, <span class="py-src-string">'example-domain.com'</span>),
<span class="py-src-variable">MX</span>(<span class="py-src-string">'example-domain.com'</span>, <span class="py-src-number">0</span>, <span class="py-src-string">'mail.example-domain.com'</span>),
<span class="py-src-variable">A</span>(<span class="py-src-string">'mail.example-domain.com'</span>, <span class="py-src-string">'123.0.16.43'</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">twistd -n dns --pyzone
example-domain.com</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>
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<span class="version">Version: 13.1.0</span>
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