<?xml version="1.0"?> <html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/><title>courierpop3d</title><link rel="stylesheet" href="style.css" type="text/css"/><meta name="generator" content="DocBook XSL Stylesheets V1.75.2"/><link rel="home" href="#id375752" title="courierpop3d"/><link xmlns="" rel="stylesheet" type="text/css" href="manpage.css"/><meta xmlns="" name="MSSmartTagsPreventParsing" content="TRUE"/><link xmlns="" rel="icon" href="icon.gif" type="image/gif"/><!-- Copyright 1998 - 2009 Double Precision, Inc. See COPYING for distribution information. --></head><body><div class="refentry" title="courierpop3d"><a id="id375752" 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" title="Synopsis"><h2>Synopsis</h2><div class="cmdsynopsis"><p><code class="command">/usr/sbin/couriertcpd</code> {-nodnslookup} {-stderr=syslog} {110} {/usr/lib64/courier-imap/courier/courierpop3login} [<em class="replaceable"><code>modules</code></em>...] {/usr/lib64/courier-imap/courier/courierpop3d} {./Maildir}</p></div></div><div class="refsect1" title="DESCRIPTION"><a id="id375544" shape="rect"> </a><h2>DESCRIPTION</h2><p> This is a simple POP3 server for Maildirs.</p><div class="note" title="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" title="SEE ALSO"><a id="id374653" 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>