1168515Sgshapiro<HTML> 2168515Sgshapiro<HEAD> 3168515Sgshapiro<TITLE>Filtering Mail with Sendmail</TITLE> 4168515Sgshapiro</HEAD> 5168515Sgshapiro<BODY> 690792Sgshapiro<!-- 7266527Sgshapiro$Id: index.html,v 1.14 2013-11-22 20:51:39 ca Exp $ 890792Sgshapiro--> 990792Sgshapiro 10168515Sgshapiro<H1>Filtering Mail with Sendmail</H1> 1190792Sgshapiro 1290792Sgshapiro<!-- 13168515Sgshapiro<P><B>Disclaimer</B>: 1490792SgshapiroThis preliminary API description is provided for review only. This 1590792Sgshapirospecification may change based on feedback from reviewers, and does 1690792Sgshapironot bind Sendmail to offer this functionality in any release. 1790792Sgshapiro--> 1890792Sgshapiro 19168515Sgshapiro<H2>Introduction</H2> 2090792Sgshapiro 2190792Sgshapiro<P> 2290792SgshapiroSendmail's Content Management API (milter) provides third-party 2390792Sgshapiroprograms to access mail messages as they are being processed by the 2490792SgshapiroMail Transfer Agent (MTA), allowing them to examine and modify message 2590792Sgshapirocontent and meta-information. Filtering policies implemented by 2690792SgshapiroMilter-conformant filters may then be centrally configured and 2790792Sgshapirocomposed in an end-user's MTA configuration file. 2890792Sgshapiro 29168515Sgshapiro<P> 3090792SgshapiroPossible uses for filters include spam rejection, virus 3190792Sgshapirofiltering, and content control. In general, Milter seeks to address 3290792Sgshapirosite-wide filtering concerns in a scalable way. Individual users' mail 3390792Sgshapirofiltering needs (e.g. sorting messages by subject) are left to 34168515Sgshapiroclient-level programs such as <A href="http://www.procmail.org">Procmail</A>. 3590792Sgshapiro 3690792Sgshapiro<P> 3790792SgshapiroThis document is a technical introduction intended for those 3890792Sgshapirointerested in developing Milter filters. It includes: 39168515Sgshapiro<UL> 40168515Sgshapiro<LI>A description of Milter's design goals. 4190792Sgshapiro 42168515Sgshapiro<LI>An explanation of Milter application architecture, including 4390792Sgshapirointeractions between the support library and user code, and between 4490792Sgshapirofilters and the MTA. 4590792Sgshapiro 46168515Sgshapiro<LI>A specification of the C application programming interface. 47168515Sgshapiro<LI>An example of a simple Milter filter. 48168515Sgshapiro</UL> 4990792Sgshapiro 50168515Sgshapiro<H2>Contents</H2> 5190792Sgshapiro 52168515Sgshapiro<UL> 53168515Sgshapiro<LI><A href="design.html">Architecture</A> 54168515Sgshapiro<UL> 55168515Sgshapiro <LI>Design Goals 56168515Sgshapiro <LI>Implementing Filtering Policies 57168515Sgshapiro <LI>MTA - Filter communication 58168515Sgshapiro</UL> 59168515Sgshapiro<LI><A href="overview.html">Technical Overview</A> 60168515Sgshapiro<UL> 61168515Sgshapiro <LI>Initialization 62168515Sgshapiro <LI>Control flow 63168515Sgshapiro <LI>Multithreading 64168515Sgshapiro <LI>Resource Management 65168515Sgshapiro <LI>Signal Handling 66168515Sgshapiro</UL> 67168515Sgshapiro<LI><A href="api.html">API Documentation</A> 68168515Sgshapiro<UL> 69168515Sgshapiro <LI>Library Control Functions 70168515Sgshapiro <LI>Data Access Functions 71168515Sgshapiro <LI>Message Modification Functions 72168515Sgshapiro <LI>Callbacks 73168515Sgshapiro</UL> 74168515Sgshapiro<LI><A href="installation.html">Installation and Configuration</A> 75168515Sgshapiro<UL> 76168515Sgshapiro <LI>Compiling and Installing Your Filter 77168515Sgshapiro <LI>Configuring Sendmail 78168515Sgshapiro</UL> 79168515Sgshapiro<LI><A href="sample.html">A Sample Filter</A> 80168515Sgshapiro<!-- <LI><A href="other.html">Other Sources of Information</A> --> 81168515Sgshapiro</UL> 8290792Sgshapiro 83168515Sgshapiro<HR size="1"> 84168515Sgshapiro<FONT size="-1"> 85261194SgshapiroCopyright (c) 2000, 2001, 2003 Proofpoint, Inc. and its suppliers. 8690792SgshapiroAll rights reserved. 87168515Sgshapiro<BR> 8890792SgshapiroBy using this file, you agree to the terms and conditions set 89112810Sgshapiroforth in the LICENSE. 90168515Sgshapiro</FONT> 91168515Sgshapiro</BODY> 92168515Sgshapiro</HTML> 93