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Copyright 1998 - 2009 Double Precision, Inc.  See COPYING for distribution
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--></head><body><div class="refentry"><a id="idm255236387360" shape="rect"> </a><div class="titlepage"/><div class="refnamediv"><h2>Name</h2><p>courierpop3d — The <span class="application">Courier</span>
      POP3 server</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="cmdsynopsis"><p><code class="command">@sbindir@/couriertcpd</code>  {-nodnslookup} {-stderr=syslog} {110} {@libexecdir@/courier/courierpop3login} [<em class="replaceable"><code>modules</code></em>...] {@libexecdir@/courier/courierpop3d} {./Maildir}</p></div></div><div class="refsect1"><a id="idm255235563680" shape="rect"> </a><h2>DESCRIPTION</h2><p>
This is a simple POP3 server for Maildirs.</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
The <span class="command"><strong>couriertcpd</strong></span>, <span class="command"><strong>courierpop3login</strong></span>,
and <span class="command"><strong>courierpop3d</strong></span> modules may be installed elsewhere than
indicated here.</p></div><p>
<span class="command"><strong>courierpop3login</strong></span> is usually started by
<span class="command"><strong>couriertcpd</strong></span>. It
already expects that a POP3 client is connected to standard input and output,
presumably via a network socket.
<span class="command"><strong>courierpop3login</strong></span> reads the POP3
userid and password, then runs the
authentication <code class="literal">modules</code>. The remaining
arguments are passed along as arguments to <code class="literal">modules</code>.</p><p>
<code class="literal">modules</code>
is one or more authentication modules (see the
<a class="ulink" href="authlib.html" target="_top" shape="rect"><span class="citerefentry"><span class="refentrytitle">authlib</span>(7)</span>
</a>
manual page).</p><p>
Each authentication modules runs the program specified by its first
argument, allowing the authentication modules to be chained. The last program
in the chain is
<span class="command"><strong>courierpop3d</strong></span>
, which provides the actual POP3 service. In
accordance with the authentication protocol, as described in
<a class="ulink" href="authlib.html" target="_top" shape="rect"><span class="citerefentry"><span class="refentrytitle">authlib</span>(7)</span>
</a>
<span class="command"><strong>courierpop3d</strong></span> reads
file descriptor 3 to see if the userid/password has been succesfully
validated. If not, <span class="command"><strong>courierpop3d</strong></span> terminates.</p><p>
Otherwise, <span class="command"><strong>courierpop3d</strong></span> expects to be already running
under the
appropriate user and group id, with its current directory set to the account's
home directory.</p><p>
The first order of business is to find the account's Maildir. If the
environment variable <code class="envar">MAILDIR</code> is set, that's where we go.
That should be the
pathname to the account's Maildir. The environment variable
<code class="envar">MAILDIR</code> may be set by the
authentication module.
If <code class="envar">MAILDIR</code> is not set,
<span class="command"><strong>courierpop3d</strong></span> uses its first argument.
Usually, the default maildir is
<code class="filename">$HOME/Maildir</code>, therefore the first argument to
<span class="command"><strong>courierpop3d</strong></span> is
"<code class="literal">./Maildir</code>".</p></div><div class="refsect1"><a id="idm255235542128" shape="rect"> </a><h2>SEE ALSO</h2><p>
<a class="ulink" href="authlib.html" target="_top" shape="rect"><span class="citerefentry"><span class="refentrytitle">authlib</span>(7)</span>
</a>,
<a class="ulink" href="userdb.html" target="_top" shape="rect"><span class="citerefentry"><span class="refentrytitle">userdb</span>(8)</span>
</a>.</p></div></div></body></html>
