The qmail Handbook

583 Pages·2004·2.34 MB·English

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The qmail Handbook
by Dave Sill ISBN:1893115402
Apress 2002 (492 pages)
This guide begins with a discussion of qmail s history,
architecture and features, and then goes into a thorough
investigation of the installation and configuration process.

Table of Contents
The qmail Handbook
Introduction
Ch
apt
- Introducing qmail
er
1
Ch
apt
- Installing qmail
er
2
Ch
apt
- Configuring qmail: The Basics
er
3
Ch
apt
- Using qmail
er
4
Ch
apt
- Managing qmail
er
5
Ch
apt
- Troubleshooting qmail
er
6
Ch
apt
- Configuring qmail: Advanced Options
er
7
Ch
apt
- Controlling Junk Mail
er
8
Ch
apt
- Managing Mailing Lists
er
9
Ch
apt
- Serving Mailboxes
er
10
Ch
apt
- Hosting Virtual Domain and Users
er
11
Ch
apt
- Understanding Advanced Topics
er
12
Ap
pe
ndi - How qmail Works
x
A
Ap
pe
ndi - Related Packages
x
B
Ap
pe
ndi - How Internet Mail Works
x
C
Ap
pe
ndi - qmail Features
x
D
Ap
pe
- Error Messages
ndi
x E
Ap
pe
- Gotchas
ndi
x F
Index
List of Figures
List of Tables
List of Listings
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Back Cover

• Provides thorough instruction for installing, configuring, and optimizing qmail
• Includes coverage of secure networking, troubleshooting issues, and mailing list administration
• Covers what system administrators want to know by concentrating on qmail issues relevant to daily
operation
• Includes instructions on how to filter spam before it reaches the client
The qmail Handbook will guide system and mail administrators of all skill levels through installing, configuring, and
maintaining the qmail server. Author Dave Sill, a long-time qmail user and system administrator, as well as the author
of the popular online tutorial Life with qmail, exposes readers to all practical aspects of working with this popular
mail server.

This definitive guide begins with a discussion of qmail s history, architecture, and features and then goes into a
through investigation of the installation and configuration process. Readers will learn how to install qmail on several
operating systems and gain valuable insight into proper configuration, testing procedures, and performance tuning, all
of which are integral to a properly functioning production environment mail server. Readers will also learn how to
administer users and mail, install filters, and oversee daily qmail operation and maintenance. Throughout, Sill focuses
on topics essential to all mail administrators, elaborating upon such subjects as configuring mailing list managers,
controlling spam, secure networking, scanning for viruses, hosting virtual domains and users, and creating dial-up
clients.

The qmail Handbook is the ultimate resource for administrators and developers needing to master the functionality
of the powerful qmail software.

About the Author
Dave Sill is a professional system administrator and technical support engineer with more than 15 years experience.
He s been using qmail service since its first public release in 1996 and is the author of the popular online qmail guide
Life with qmail. He s also an active contributor to online qmail support groups, including the qmail mailing list and
Usenet newsgroup.

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The qmail Handbook
DAVE SILL
Copyright © 2002 by Dave Sill

All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means, electronic
or mechanical, including photocopying, recording, or by any information storage or retrieval system, without the prior
written permission of the copyright owner and the publisher.

ISBN (pbk): 1-893115-40-2
Printed and bound in the United States of America 12345678910

Trademarked names may appear in this book. Rather than use a trademark symbol with every occurrence of a
trademarked name, we use the names only in an editorial fashion and to the benefit of the trademark owner, with no
intention of infringement of the trademark.

Editorial Directors: Dan Appleman, Gary Cornell, Jason Gilmore, Karen Watterson

Technical Reviewer: Charles Cabazon

Project Manager: Grace Wong

Copy Editor: Kim Wimpsett

Production Editor: Sofia Marchant

Compositor: Impressions Book and Journal Services, Inc.

Indexer: Ron Strauss

Cover Designer: Tom Debolski

Marketing Manager: Stephanie Rodriguez
Distributed to the book trade in the United States by Springer-Verlag New York, Inc.,175 Fifth Avenue, New
York, NY, 10010
and outside the United States by Springer-Verlag GmbH & Co. KG, Tiergartenstr. 17, 69112 Heidelberg, Germany
In the United States, phone 1-800-SPRINGER, email <[email protected]>, or visit
http://www.springer-ny.com.
Outside the United States, fax [phone], email <[email protected]>, or visit http://www.springer.de.

For information on translations, please contact Apress directly at 901 Grayson Street, Suite 204, Berkeley, CA
94710.
Phone [phone], fax: [phone], email <[email protected]>, or visit http://www.apress.com.

The information in this book is distributed on an "as is" basis, without warranty. Although every precaution has been
taken in the preparation of this work, neither the author nor Apress shall have any liability to any person or entity with
respect to any loss or damage caused or alleged to be caused directly or indirectly by the information contained in
this work.

The source code for this book is available to readers at http://www.apress.com in the Downloads section. You will
need to answer questions pertaining to this book in order to successfully download the code.
For my mother
Acknowledgments
Thanks to dan bernstein for giving us qmail and many other packages including the daemontools and ucspi-tcp
support utilities. Thanks also to the many people who helped make my online guide "Life with qmail" what it is today
and to the members of the qmail mailing list who have helped me learn a great deal about qmail over the years.

Thanks also to the fine folks at Apress: Jason Gilmore and Gary Cornell, for not only taking a chance on a first-time
author but actively recruiting him; Grace Wong, for managing the project; Kim Wimpsett, for turning my crude
writings into clear and consistent text; Tory McLearn and Sofia Marchant, for laying out the book; Stephanie
Rodriguez, for her marketing efforts; and the many others behind the scenes who I didn't deal with directly. Working
with Apress was a joy: They were supportive and committed to producing a high-quality book.

Thanks to Charles Cazabon, the technical reviewer. His suggestions were valuable and dramatically improved the
quality of the finished product. This will come as no surprise to anyone who has seen his contributions to the qmail list.

Finally, special thanks to my family and friends who encouraged, supported, and tolerated me throughout the project.
My wife, Mary Jane, convinced me to write this book even though she knew it would be painful for the family at
times. My children Andy, Rachel, and Erica enthusiastically supported me and helped out in many ways. Andy tested
the installation instructions in Chapter 2 on four Linux distributions and three BSD distributions. My father took over
most of my chores around the house and farm for six months in addition to his usual cooking and
house/dog/kid-sitting duties. My mother has supported me throughout my life. Her strength is inspiring. Many other
friends and family members supported this effort. Some are acknowledged throughout the book in the names used in
examples, but I'm sure I left some out.

Dave Sill, September 2001
About the Author
Dave sill is a professional system administrator and technical support engineer with more than 15 years of experience.
He's been using qmail since its first public release in 1996 and is the author of the popular online qmail guide, "Life
with qmail." He's also an active contributor to online qmail support groups including the qmail mailing list and Usenet
newsgroup. He lives with his wife, children, and an assortment of dogs, cats, cows, chickens, and turkeys on a
31-acre farm in east Tennessee. When he has spare time, he brews his own beer and trains in Isshinryu karate.

About the Technical Reviewer
Charles Cazabon is a software systems developer with 15 years of experience in computing and information
technology. He has been using and configuring qmail since 1998 and is the author of several free software programs,
including getmail, queue-repair, and memtester. He is also an active participant in the qmail mailing list. He lives in
Saskatoon, Canada, with his significant other, two salamanders, six hamsters, and two mice.

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Introduction

This book documents how to install, configure, and use qmail. It will be most beneficial to system, network, and mail
administrators, but it will also be helpful to users who want to read and send e-mail more effectively.

What Can You Expect to Learn from This Book?

You can expect to learn the following:

•
What qmail is, what it can do, and what it can't do

•
How to install and configure a basic qmail server, including various support utilities

•
How to use qmail as a regular user: controlling the disposition of incoming messages, formatting outgoing
messages, and working with mailboxes in multiple formats

•
How to manage a qmail server: setting up aliases, users, virtual domains, and mailing lists; troubleshooting;
performance tuning; and controlling junk mail and other abuse

•
How qmail works: not just what it does, but how it does it

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Organization

Chapter 1, "Introducing qmail," describes qmail and its features. Read it if you're not sure exactly what qmail is or
what it can do for you. It also describes the overall organization of the qmail suite, compares qmail to other Unix
mailers, and lists other sources of qmail information and support.

Chapter 2, "Installing qmail," describes step-by-step the installation of qmail on a wide range of operating system
distributions, including commercial Unix variants, Linux, and various Berkeley Software Distributions (BSDs).

Chapter 3, "Configuring qmail: The Basics," shows how to configure qmail for a variety of basic functions.

Chapter 4, "Using qmail," covers how users read and send messages.

Chapter 5," Managing qmail," covers the qmailctl script, queue management, and administrative commands.

Chapter 6, "Troubleshooting qmail," shows how to monitor the qmail processes, understand the log files, analyze
message headers, conduct tests, and diagnose common problems.

Chapter 7, "Configuring qmail: Advanced Options," shows how to configure qmail for a variety of typical
configurations, migrate Sendmail systems to qmail, and use source-code modifications. It also shows how to use the
QMTP and QMQP protocols, enable secure networking, and improve the performance of your qmail system.

Chapter 8, "Controlling Junk Mail," covers methods for dealing with unwanted mail at both the system and user levels.

Chapter 9, "Managing Mailing Lists," details installing and using three popular mailing list managers with qmail: ezmlm,
Majordomo, and Mailman.

Chapter 10, "Serving Mailboxes," shows how to provide remote access to users' mailboxes via the POP3 and IMAP
protocols.

Chapter 11, "Hosting Virtual Domains and Users," covers two popular qmail add-ons for managing virtual domains
and virtual users: VmailMgr and Vpopmail.

Chapter 12, "Understanding Advanced Topics," explains from a qmail perspective some advanced topics such as
scalable server "farms," accessing user information via LDAP or SQL, and the Variable Envelope Return Path
(VERP) mechanism that qmail uses for reliable automatic bounce handling.
The appendices cover:

•
How qmail works

•
Related packages

•
How Internet mail works

•
qmail's features

•
Error messages

•
Gotchas

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Audience

This book is aimed at anyone interested in running qmail, from the rank amateur (newbie) who just installed Linux on
a spare computer all the way up to the experienced system administrator or mail administrator.

However, installing, configuring, and maintaining a mailer is a complex task. If you're not an experienced system
administrator, you probably shouldn't attempt to switch an existing mail system with thousands of users to qmail until
you're comfortable with using and managing Unix systems.

If you're a complete Unix/Linux newbie, you should start with a good introduction to Unix for users such as The
Unix Operating System by Kaare Christian. While you're reading that book, experiment on your own system. Until
you actually do the tasks you've read about, you won't really understand what you're doing and you'll probably forget
most of it before you really need it.

If you're an experienced Unix/Linux user, but you're not familiar with system administration, many good books are
available. The best is probably Unix System Administration Handbook by Nemeth, et al., which covers most of
the common Unix variants, including Solaris, HP-UX, Red Hat Linux, and FreeBSD. If possible, select one specific
to the variant of Unix or Linux that you'll be using. Although all flavors of Unix look pretty similar to users, they differ
substantially in the details of system administration.

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