Mail Administration Guide Sun Microsystems, Inc. 2550 Garcia Avenue Mountain View, CA 94043-1100 U.S.A. Part No: 802-5827 August 1997 Copyright 1997 Sun Microsystems, Inc. 901 San Antonio Road, Palo Alto, California 94303-4900 U.S.A. All rights reserved. This product or document is protected by copyright and distributed under licenses restricting its use, copying, distribution, and decompilation. No part of this product or document may be reproduced in any form by any means without prior written authorization of Sun and its licensors, if any. Third-party software, including font technology, is copyrighted and licensed from Sun suppliers. Parts of the product may be derived from Berkeley BSD systems, licensed from the University of California. UNIX is a registered trademark in the U.S. and other countries, exclusively licensed through X/Open Company, Ltd. 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Aucune partie de ce produit ou document ne peut être reproduite sous aucune forme, par quelque moyen que ce soit, sans l’autorisation préalable et écrite de Sun et de ses bailleurs de licence, s’il y en a. Le logiciel détenu par des tiers, et qui comprend la technologie relative aux polices de caractères, est protégé par un copyright et licencié par des fournisseurs de Sun. Des parties de ce produit pourront être dérivées du système Berkeley BSD licenciés par l’Université de Californie. UNIX est une marque déposée aux Etats-Unis et dans d’autres pays et licenciée exclusivement par X/Open Company, Ltd. Sun, Sun Microsystems, le logo Sun, SunSoft, SunDocs, SunExpress, SunOS, OpenWindows, DeskSet, ONC, NFS, et Solaris sont des marques de fabrique ou des marques déposées, ou marques de service, de Sun Microsystems, Inc. aux Etats-Unis et dans d’autres pays. Toutes les marques SPARC sont utilisées sous licence et sont des marques de fabrique ou des marques déposées de SPARC International, Inc. aux Etats-Unis et dans d’autres pays. Les produits portant les marques SPARC sont basés sur une architecture développée par Sun Microsystems, Inc. L’interface d’utilisation graphique OPEN LOOK et SunTM a été développée par Sun Microsystems, Inc. pour ses utilisateurs et licenciés. Sun reconnaît les efforts de pionniers de Xerox pour la recherche et le développement du concept des interfaces d’utilisation visuelle ou graphique pour l’industrie de l’informatique. Sun détient une licence non exclusive de Xerox sur l’interface d’utilisation graphique Xerox, cette licence couvrant également les licenciés de Sun qui mettent en place l’interface d’utilisation graphique OPEN LOOK et qui en outre se conforment aux licences écrites de Sun. CETTE PUBLICATION EST FOURNIE “EN L’ETAT” ET AUCUNE GARANTIE, EXPRESSE OU IMPLICITE, N’EST ACCORDEE, Y COMPRIS DES GARANTIES CONCERNANT LA VALEUR MARCHANDE, L’APTITUDE DE LA PUBLICATION A REPONDRE A UNE UTILISATION PARTICULIERE, OU LE FAIT QU’ELLE NE SOIT PAS CONTREFAISANTE DE PRODUIT DE TIERS. CE DENI DE GARANTIE NE S’APPLIQUERAIT PAS, DANS LA MESURE OU IL SERAIT TENU JURIDIQUEMENT NUL ET NON AVENU. Please Recycle Contents Preface vii 1. Understanding Mail Services 1 Mail Services Terminology 1 Mail Services Software Terminology 2 Hardware Components of a Mail Configuration 9 Mail Service Programs and Files 12 How Mail Addressing Works 20 Planning Your Mail System 21 Local Mail Only 22 Local Mail in Remote Mode 23 Local Mail and a Remote Connection 23 Two Domains and a Gateway 24 2. Setting Up and Administering Mail Services 27 Setting Up Mail Services 27 Setting Up Mail Security 29 r How to Set Up a Mail Server 29 r How to Set Up a Mail Client 29 r How to Set Up a Mail Host 31 r How to Set Up a Mail Gateway 31 Contents iii Creating Mail Aliases 32 Mail Alias Files 33 r How to List the Contents of an NIS+ Aliases Table 36 r How to Add Aliases to a NIS+ mail_aliases Table From the Command Line 37 r How to Add Entries by Editing a NIS+ mail_aliases Table 38 r How to Change Entries in a NIS+ mail_aliases Table 38 r How to Delete Entries From a NIS+ mail_aliases Table 39 Setting Up NIS mail.aliases Map 39 Setting Up Local Mail Aliases Files 40 Setting Up DNS Aliases Files 41 Setting Up the Postmaster Alias 42 Testing the Mail Configuration 43 r How to Test the Mail Configuration 43 Administering the Mail Configuration 44 Postmaster Duties 44 r How to Print the Queue 46 r How to Force the Queue 47 r How to Run a Subset of the Mail Queue 47 r How to Move the Queue 47 r How to Run the Old Mail Queue 48 System Log 48 Troubleshooting Tips 50 r How to Check Aliases 50 r How to Test the sendmail Rule Sets 50 r How to Verify Connections to Other Systems 51 Other Diagnostic Information 51 3. Customizing sendmail Configuration Files 53 iv Mail Administration Guide ♦ August 1997 sendmail Overview 54 sendmail Features 54 sendmail Functions 55 sendmail Interfaces 55 How sendmail Works 56 Argument Processing and Address Parsing 56 Message Collection 57 Message Delivery 58 Error Handling 58 Message Header Editing 59 Configuration File 59 sendmail Implementation 59 Mail to Files and Programs 59 Configuration Overview 60 Arguments to sendmail 61 Queue Interval 61 Daemon Mode 62 Debugging 62 Trying a Different Configuration File 62 Tuning Configuration Parameters 63 Time Values 63 Delivery Mode 64 Load Limiting 65 Log Level 65 File Modes 66 sendmail Configuration File 67 Purpose of the sendmail Configuration File 68 sendmail Configuration File Syntax 69 Contents v R and S-Rewriting Rules 74 Address-Rewriting Rules 76 Building a Configuration File 86 How sendmail Interacts With a Name Service 88 Setting Up sendmail Requirements for Name Services 89 r How to Configure NIS for sendmail 90 r How to Configure NIS and DNS for sendmail 91 r How to Configure NIS+ for sendmail 91 r How to Configure NIS+ and DNS for sendmail 92 Command-Line Arguments to sendmail 93 Configuration Options to sendmail 94 Mailer Flags 95 A. sendmail Configuration File 97 A Sample sendmail Configuration File 97 B. sendmail Options 107 sendmail Command-Line Arguments 107 sendmail Configuration Options 109 Mailer Flags 115 Index 119 vi Mail Administration Guide ♦ August 1997 Preface Mail Administration Guide presents the concepts and procedures required to establish and maintain electronic mail services, with special focus on the configuration files needed for sendmail. Prior to using this book, you should have already installed SunOSTM 5.x software and set up the networking software that you plan to use. Who Should Use This Book This book is intended for the system administrator whose responsibilities include setting up and maintaining mail services. Though much of the book is directed toward the experienced system administrator, it also contains information useful to novice administrators and other readers who may be new to the SolarisTM platform. How This Book Is Organized Chapter 1 provides an overview of the mail service. The concepts and terminology necessary to set up and maintain a mail service are discussed in detail. Chapter 2 describes the steps required to set up and administer a mail service. Troubleshooting tips are included. Chapter 3 explains how to edit the files that sendmail consults. Appendix A includes a reference copy of the generic main.cf file. Preface vii Appendix B lists the command-line arguments and the configuration options to sendmail, and the mailer flags. Related Books This is a list of related documentation that is refered to in this book. TCP/IP and Data Communications Administration Guide System Administration Guide sendmail, Second Edition, by Bryan Costales (O’Reilly & Associates, Inc., 1997) !%@:: A Directory of Electronic Mail Addressing and Networks, by Donnalyn Frey and Rick Adams Ordering Sun Documents The SunDocsSM program provides more than 250 manuals from Sun Microsystems, Inc. If you live in the United States, Canada, Europe, or Japan, you can purchase documentation sets or individual manuals using this program.