1<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" 2 "http://www.w3.org/TR/html4/loose.dtd"> 3 4<html> 5 6<head> 7 8<title>Postfix memcache client Howto</title> 9 10<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 11<link rel='stylesheet' type='text/css' href='postfix-doc.css'> 12 13</head> 14 15<body> 16 17<h1><img src="postfix-logo.jpg" width="203" height="98" ALT="">Postfix memcache client Howto</h1> 18 19<hr> 20 21<h2>Introduction</h2> 22 23<p>The Postfix memcache client allows you to hook up Postfix to a 24memcache server. The current implementation supports one memcache 25server per Postfix table, with one optional Postfix database that 26provides persistent backup. The Postfix memcache client supports 27the lookup, update, delete and sequence operations. The sequence 28(i.e. first/next) operation requires a backup database that supports 29this operation. </p> 30 31<p> Typically, the Postfix memcache client is used to reduce query 32load on a persistent database, but it may also be used to query a 33memory-only database for low-value, easy-to-recreate, information 34such as a reputation cache for postscreen(8), verify(8) or greylisting. 35</p> 36 37<h2>Limitations</h2> 38 39<ul> 40 41<li> <p> The Postfix memcache client cannot be used for security-sensitive 42tables such as <tt>alias_maps</tt> (these may contain "<tt>|command</tt>" 43and "<tt>/file/name</tt>" destinations), or <tt>virtual_uid_maps</tt>, 44<tt>virtual_gid_maps</tt> and <tt>virtual_mailbox_maps</tt> (these 45specify UNIX process privileges or "<tt>/file/name</tt>" destinations). 46Typically, a memcache database is writable by any process that can 47talk to the memcache server; in contrast, security-sensitive tables 48must never be writable by the unprivileged Postfix user. </p> 49 50<li> <p> The Postfix memcache client requires additional configuration 51when used as postscreen(8) or verify(8) cache. For details see the 52<tt>backup</tt> and <tt>ttl</tt> parameter discussions in the 53memcache_table(5) manual page. </p> 54 55</ul> 56 57<h2>Building Postfix with memcache support</h2> 58 59<p>The Postfix memcache client has no external dependencies, 60and is therefore built into Postfix by default. </p> 61 62<h2>Configuring memcache lookup tables</h2> 63 64<p> Configuration is described in the memcache_table(5) manpage. </p> 65 66<h2>Credits</h2> 67 68<p> The first memcache client for Postfix was written by Omar Kilani, 69and was based on the libmemcache library. </p> 70 71<p> Wietse wrote the current memcache client from the ground up for 72Postfix version 2.9. This implementation does not use libmemcache, 73and bears no resemblance to earlier work. </p> 74 75</body> 76 77</html> 78
