<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html> <head> <link rel="STYLESHEET" href="mailman-admin.css" type='text/css' /> <link rel="first" href="mailman-admin.html" title='GNU mailman - list Administration Manual' /> <link rel='contents' href='contents.html' title="Contents" /> <link rel='last' href='about.html' title='About this document...' /> <link rel='help' href='about.html' title='About this document...' /> <link rel="prev" href="node6.html" /> <link rel="parent" href="node3.html" /> <link rel="next" href="node8.html" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name='aesop' content='information' /> <title>1.4 Basic Architectural Overview</title> </head> <body> <div class="navigation"> <div id='top-navigation-panel' xml:id='top-navigation-panel'> <table align="center" width="100%" cellpadding="0" cellspacing="2"> <tr> <td class='online-navigation'><a rel="prev" title="1.3 a List's Web" href="node6.html"><img src='previous.png' border='0' height='32' alt='Previous Page' width='32' /></a></td> <td class='online-navigation'><a rel="parent" title="1 introduction to GNU" href="node3.html"><img src='up.png' border='0' height='32' alt='Up one Level' width='32' /></a></td> <td class='online-navigation'><a rel="next" title="2 the List Configuration" href="node8.html"><img src='next.png' border='0' height='32' alt='Next Page' width='32' /></a></td> <td align="center" width="100%">GNU Mailman - List Administration Manual</td> <td class='online-navigation'><a rel="contents" title="Table of Contents" href="contents.html"><img src='contents.png' border='0' height='32' alt='Contents' width='32' /></a></td> <td class='online-navigation'><img src='blank.png' border='0' height='32' alt='' width='32' /></td> <td class='online-navigation'><img src='blank.png' border='0' height='32' alt='' width='32' /></td> </tr></table> <div class='online-navigation'> <b class="navlabel">Previous:</b> <a class="sectref" rel="prev" href="node6.html">1.3 A List's Web</a> <b class="navlabel">Up:</b> <a class="sectref" rel="parent" href="node3.html">1 Introduction to GNU</a> <b class="navlabel">Next:</b> <a class="sectref" rel="next" href="node8.html">2 The List Configuration</a> </div> <hr /></div> </div> <!--End of Navigation Panel--> <h2><a name="SECTION002140000000000000000"> 1.4 Basic Architectural Overview</a> </h2> <p> This section will outline the basic architecture of GNU Mailman, such as how messages are processed by the sytem. Without going into lots of detail, this information will help you understand how the configuration options control Mailman's functionality. <p> When mail enters the system from your mail server, it is dropped into one of several Mailman <em>queues</em> depending on the address the message was sent to. For example, if your system has a mailing list named <var>mylist</var> and your domain is <var>example.com</var>, people can post messages to your list by sending them to <var>mylist@example.com</var>. These messages will be dropped into the <em>incoming</em> queue, which is also colloquially called the <em>moderate-and-munge</em> queue. The incoming queue is where most of the approval process occurs, and it's also where the message is prepared for sending out to the list membership. <p> There are separate queues for the built-in archiver, the bounce processor, the email command processor, as well as the outgoing email and news queues. There's also a queue for messages generated by the Mailman system. Each of these queues typically has one <em>queue runner</em> (or ``qrunner'') that processes messages in the queue. The qrunners are idle when there are no messages to process. <p> Every message in the queues are represented by two files, a message file and a metadata file. Both of these files share the same base name, which is a combination of a unique hash and the Unix time that the message was received. The metadata file has a suffix of <span class="file">.db</span> and the message file has a suffix of either <span class="file">.msg</span> if stored in plain text, or <span class="file">.pck</span> if stored in a more efficient internal representation<a name="tex2html1" href="#foot39"><sup>1</sup></a>. <p> As a message moves through the incoming queue, it performs various checks on the message, such as whether it matches one of the moderation criteria, or contains disallowed MIME types. Once a message is approved for sending to the list membership, the message is prepared for sending by deleting, adding, or changing message headers, adding footers, etc. Messages in the incoming queue may also be stored for appending to digests. <p> <br><hr><h4>Footnotes</h4> <dl> <dt><a name="foot39">... representation</a><A HREF="node7.html#tex2html1"><sup>1</sup></a></dt> <dd>Specifically, a Python pickle </dd> </dl> <div class="navigation"> <div class='online-navigation'> <p></p><hr /> <table align="center" width="100%" cellpadding="0" cellspacing="2"> <tr> <td class='online-navigation'><a rel="prev" title="1.3 a List's Web" href="node6.html"><img src='previous.png' border='0' height='32' alt='Previous Page' width='32' /></a></td> <td class='online-navigation'><a rel="parent" title="1 introduction to GNU" href="node3.html"><img src='up.png' border='0' height='32' alt='Up one Level' width='32' /></a></td> <td class='online-navigation'><a rel="next" title="2 the List Configuration" href="node8.html"><img src='next.png' border='0' height='32' alt='Next Page' width='32' /></a></td> <td align="center" width="100%">GNU Mailman - List Administration Manual</td> <td class='online-navigation'><a rel="contents" title="Table of Contents" href="contents.html"><img src='contents.png' border='0' height='32' alt='Contents' width='32' /></a></td> <td class='online-navigation'><img src='blank.png' border='0' height='32' alt='' width='32' /></td> <td class='online-navigation'><img src='blank.png' border='0' height='32' alt='' width='32' /></td> </tr></table> <div class='online-navigation'> <b class="navlabel">Previous:</b> <a class="sectref" rel="prev" href="node6.html">1.3 A List's Web</a> <b class="navlabel">Up:</b> <a class="sectref" rel="parent" href="node3.html">1 Introduction to GNU</a> <b class="navlabel">Next:</b> <a class="sectref" rel="next" href="node8.html">2 The List Configuration</a> </div> </div> <hr /> <span class="release-info">Release 2.1, documentation updated on December 14, 2009.</span> </div> <!--End of Navigation Panel--> </body> </html>