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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd">
<!-- Copyright 1998 - 2009 Double Precision, Inc. See COPYING for -->
<!-- distribution information. -->
<refentry>
<info><author><firstname>Sam</firstname><surname>Varshavchik</surname><contrib>Author</contrib></author><productname>Courier Mail Server</productname></info>
<refmeta>
<refentrytitle>courierpop3d</refentrytitle>
<manvolnum>8</manvolnum>
<refmiscinfo>Double Precision, Inc.</refmiscinfo>
</refmeta>
<refnamediv>
<refname>courierpop3d</refname>
<refpurpose>The <application moreinfo="none">Courier</application>
POP3 server</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis sepchar=" ">
<command moreinfo="none">@sbindir@/couriertcpd</command>
<arg choice="req" rep="norepeat">-nodnslookup</arg>
<arg choice="req" rep="norepeat">-stderr=syslog</arg>
<arg choice="req" rep="norepeat">110</arg>
<arg choice="req" rep="norepeat">@libexecdir@/courier/courierpop3login</arg>
<arg choice="opt" rep="repeat"><replaceable>modules</replaceable></arg>
<arg choice="req" rep="norepeat">@libexecdir@/courier/courierpop3d</arg>
<arg choice="req" rep="norepeat">./Maildir</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>DESCRIPTION</title>
<para>
This is a simple POP3 server for Maildirs.</para>
<note>
<para>
The <command moreinfo="none">couriertcpd</command>, <command moreinfo="none">courierpop3login</command>,
and <command moreinfo="none">courierpop3d</command> modules may be installed elsewhere than
indicated here.</para>
</note>
<para>
<command moreinfo="none">courierpop3login</command> is usually started by
<command moreinfo="none">couriertcpd</command>. It
already expects that a POP3 client is connected to standard input and output,
presumably via a network socket.
<command moreinfo="none">courierpop3login</command> reads the POP3
userid and password, then runs the
authentication <literal moreinfo="none">modules</literal>. The remaining
arguments are passed along as arguments to <literal moreinfo="none">modules</literal>.</para>
<para>
<literal moreinfo="none">modules</literal>
is one or more authentication modules (see the
<ulink url="authlib.html"><citerefentry>
<refentrytitle>authlib</refentrytitle>
<manvolnum>7</manvolnum>
</citerefentry>
</ulink>
manual page).</para>
<para>
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
<command moreinfo="none">courierpop3d</command>
, which provides the actual POP3 service. In
accordance with the authentication protocol, as described in
<ulink url="authlib.html"><citerefentry>
<refentrytitle>authlib</refentrytitle>
<manvolnum>7</manvolnum>
</citerefentry>
</ulink>
<command moreinfo="none">courierpop3d</command> reads
file descriptor 3 to see if the userid/password has been succesfully
validated. If not, <command moreinfo="none">courierpop3d</command> terminates.</para>
<para>
Otherwise, <command moreinfo="none">courierpop3d</command> expects to be already running
under the
appropriate user and group id, with its current directory set to the account's
home directory.</para>
<para>
The first order of business is to find the account's Maildir. If the
environment variable <envar>MAILDIR</envar> is set, that's where we go.
That should be the
pathname to the account's Maildir. The environment variable
<envar>MAILDIR</envar> may be set by the
authentication module.
If <envar>MAILDIR</envar> is not set,
<command moreinfo="none">courierpop3d</command> uses its first argument.
Usually, the default maildir is
<filename moreinfo="none">$HOME/Maildir</filename>, therefore the first argument to
<command moreinfo="none">courierpop3d</command> is
"<literal moreinfo="none">./Maildir</literal>".</para>
</refsect1>
<refsect1>
<title>SEE ALSO</title>
<para>
<ulink url="authlib.html"><citerefentry>
<refentrytitle>authlib</refentrytitle>
<manvolnum>7</manvolnum>
</citerefentry>
</ulink>,
<ulink url="userdb.html"><citerefentry>
<refentrytitle>userdb</refentrytitle>
<manvolnum>8</manvolnum>
</citerefentry>
</ulink>.</para>
</refsect1>
</refentry>
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