1168515Sgshapiro<HTML> 2168515Sgshapiro<HEAD> 3168515Sgshapiro<TITLE>Filtering Mail with Sendmail</TITLE> 4132943Sgshapiro</HEAD> 5266692Sgshapiro<BODY> 6132943Sgshapiro<!-- 7168515Sgshapiro$Id: index.html,v 1.14 2013-11-22 20:51:39 ca Exp $ 890792Sgshapiro--> 9168515Sgshapiro 1090792Sgshapiro<H1>Filtering Mail with Sendmail</H1> 11168515Sgshapiro 12168515Sgshapiro<!-- 1390792Sgshapiro<P><B>Disclaimer</B>: 1490792SgshapiroThis preliminary API description is provided for review only. This 15168515Sgshapirospecification may change based on feedback from reviewers, and does 1690792Sgshapironot bind Sendmail to offer this functionality in any release. 17168515Sgshapiro--> 1890792Sgshapiro 19168515Sgshapiro<H2>Introduction</H2> 2090792Sgshapiro 2190792Sgshapiro<P> 22168515SgshapiroSendmail's Content Management API (milter) provides third-party 23168515Sgshapiroprograms to access mail messages as they are being processed by the 24168515SgshapiroMail Transfer Agent (MTA), allowing them to examine and modify message 25168515Sgshapirocontent and meta-information. Filtering policies implemented by 26168515SgshapiroMilter-conformant filters may then be centrally configured and 27168515Sgshapirocomposed in an end-user's MTA configuration file. 28168515Sgshapiro 29168515Sgshapiro<P> 30168515SgshapiroPossible uses for filters include spam rejection, virus 31168515Sgshapirofiltering, and content control. In general, Milter seeks to address 32168515Sgshapirosite-wide filtering concerns in a scalable way. Individual users' mail 3390792Sgshapirofiltering needs (e.g. sorting messages by subject) are left to 3490792Sgshapiroclient-level programs such as <A href="http://www.procmail.org">Procmail</A>. 35168515Sgshapiro 36168515Sgshapiro<P> 37168515SgshapiroThis document is a technical introduction intended for those 38168515Sgshapirointerested in developing Milter filters. It includes: 39168515Sgshapiro<UL> 40168515Sgshapiro<LI>A description of Milter's design goals. 41168515Sgshapiro 42168515Sgshapiro<LI>An explanation of Milter application architecture, including 4390792Sgshapirointeractions between the support library and user code, and between 4490792Sgshapirofilters and the MTA. 45168515Sgshapiro 46168515Sgshapiro<LI>A specification of the C application programming interface. 47168515Sgshapiro<LI>An example of a simple Milter filter. 48168515Sgshapiro</UL> 49168515Sgshapiro 50168515Sgshapiro<H2>Contents</H2> 51168515Sgshapiro 5290792Sgshapiro<UL> 53168515Sgshapiro<LI><A href="design.html">Architecture</A> 54168515Sgshapiro<UL> 55261363Sgshapiro <LI>Design Goals 5690792Sgshapiro <LI>Implementing Filtering Policies 57168515Sgshapiro <LI>MTA - Filter communication 5890792Sgshapiro</UL> 59112810Sgshapiro<LI><A href="overview.html">Technical Overview</A> 60168515Sgshapiro<UL> 61168515Sgshapiro <LI>Initialization 62168515Sgshapiro <LI>Control flow 63 <LI>Multithreading 64 <LI>Resource Management 65 <LI>Signal Handling 66</UL> 67<LI><A href="api.html">API Documentation</A> 68<UL> 69 <LI>Library Control Functions 70 <LI>Data Access Functions 71 <LI>Message Modification Functions 72 <LI>Callbacks 73</UL> 74<LI><A href="installation.html">Installation and Configuration</A> 75<UL> 76 <LI>Compiling and Installing Your Filter 77 <LI>Configuring Sendmail 78</UL> 79<LI><A href="sample.html">A Sample Filter</A> 80<!-- <LI><A href="other.html">Other Sources of Information</A> --> 81</UL> 82 83<HR size="1"> 84<FONT size="-1"> 85Copyright (c) 2000, 2001, 2003 Proofpoint, Inc. and its suppliers. 86All rights reserved. 87<BR> 88By using this file, you agree to the terms and conditions set 89forth in the LICENSE. 90</FONT> 91</BODY> 92</HTML> 93