Life with qmail

Dave Sill
23 September 2000

Table of Contents

1. Introduction

1.1. Audience

Life with qmail is aimed at everyone interested in running qmail, from the rank amateur (newbie) who just installed Linux on a spare PC all the way up to the experienced system administrator or mail administrator. If you find it lacking or unclear, please let me know. Send comments to

There's a wealth of information available on qmail from a variety of sources. Some is targeted to newbies, some assumes that the reader is more experienced. Life with qmail is an attempt to "glue" this information into a single source, filling in some of the cracks and assuming only that the reader has basic skills such as:

1.2. What is qmail?

qmail is an Internet Mail Transfer Agent (MTA) for UNIX-like operating systems. It's a drop-in replacement for the Sendmail system provided with UNIX operating systems. qmail uses the Simple Mail Transfer Protocol (SMTP) to exchange messages with MTA's on other systems.

Note: The name is "qmail", not "Qmail".

1.3. Why use qmail?

Your operating system included an MTA, probably Sendmail, so if you're reading this document you're probably looking for something better. Some of the advantages of qmail over vendor-provided MTA's include:

1.3.1. Security

qmail was designed for high security. Sendmail has a long history of serious security problems. When Sendmail was written, the Net was a much friendlier place. Everyone knew everyone else, and there was little need to design and code for high security. Today's Internet is a much more hostile environment for network servers. Sendmail's author, Eric Allman, has done a good job of tightening up the program, but nothing short of a redesign can achieve true security.

1.3.2. Performance

qmail parallelizes mail delivery, performing up to 20 deliveries simultaneously, by default.

1.3.3. Reliability

Once qmail accepts a message, it guarantees that it won't be lost. qmail also supports a new mailbox format that works reliably even over NFS without locking.

1.3.4. Simplicity

qmail is smaller than any other equivalently-featured MTA.

Note: The official qmail web page, covers the advantages of qmail more extensively.

1.4. History

qmail was written by Dan Bernstein (DJB),, a math professor now at the University of Illinois in Chicago. Dr. Bernstein is also well known for his work in the field of cryptography and for his lawsuit against the U.S. government regarding the publishing of encryption source code. See,4,36217,00.html?owv for information regarding the lawsuit.

The first public release of qmail, beta version 0.70, occurred on January, 24, 1996. The first gamma release, 0.90, was on August, 1, 1996.

Version 1.0, the first general release, was announced on February, 20, 1997. The current version, 1.03, was released on June, 15, 1998.

The next release is expected to be an evaluation version of 2.0. Some of things that might appear in version 2 are covered at

1.5. Features

The qmail web page,, has a comprehensive list of qmail's features. This section is based heavily on that list.

1.5.1. Setup

1.5.2. Security

1.5.3. Message construction

1.5.4. SMTP service

1.5.5. Queue management

1.5.6. Bounces

1.5.7. Routing by domain

1.5.8. SMTP delivery

1.5.9. Forwarding and mailing lists

1.5.10. Local delivery

1.5.11. POP3 service

1.6. Related packages

qmail follows the classic UNIX philosophy that each tool should perform a single, well-defined function, and complex functions should be built by connecting a series of simple tools into a "pipeline". The alternative is to build more and more complex tools that re-invent much of the functionality of the simpler tools.

It's not surprising, then, that qmail itself doesn't do everything everyone might want it to do. Here, then, are some of the most popular add-ons written for qmail. Of course, many standard UNIX utilities can also be plugged into qmail.

1.7. Architecture

Appendix D covers qmail's functional and physical structure. In a nutshell, qmail consists of a series of programs (modules) that perform different tasks.

1.8. License

qmail is copyrighted by the author, Dan Bernstein, and is not distributed with a statement of user's rights. In, he outlines what he thinks your rights are under U.S. copyright law. In he grants the right to distribute qmail source code. Binary distributions are allowed under the terms described there and in, although, at this time, nobody is actually attempting this.

The bottom line is that you can use qmail for any purpose, you can redistribute unmodified qmail source distributions and qualifying var-qmail binary distributions, and you can distribute patches to qmail. You can't distribute modified qmail source code or non-var-qmail binary distributions.

1.9. Comparison with other MTA's

A book could be written about this topic, but it would be tedious reading. Here's a quick comparison of qmail with some of the most common UNIX MTA's.

MTA Maturity Security Features Performance Sendmailish Modular
qmail medium high high high addons yes
Sendmail high low high low x no
Postfix low high medium high yes yes
exim medium low high medium yes no

Sendmailish means the MTA behaves like Sendmail in some ways that would make a switch from Sendmail to the alternative MTA more user-transparent, such as the use of .forward files, /etc/aliases, and delivery to /var/spool/mail.

Cameron Laird has a web page comparing these and other free and commercial MTA's at

1.10. Documentation

1.10.1. man pages

The qmail distribution comes with a complete set of man pages. After installation, they're in /var/qmail/man. You'll probably need to add that directory to your MANPATH environment variable.

Shell Command
Bourne (/bin/sh) MANPATH=$MANPATH:/var/qmail/man; export MANPATH
bash, Korn export MANPATH=$MANPATH:/var/qmail/man
C Shell setenv MANPATH $MANPATH:/var/qmail/man

At this point, commands in the format "man name-of-qmail-man-page" should display the appropriate man page.

The man pages are also available on-line in HTML format from:

Note: the qmail man pages are loaded with information, but they require careful reading because they're written in a very dense, technical style. You might want to print off a set and read them through once to familiarize yourself with what's there and where it is. Very little information is repeated on multiple pages, so if you don't know where something is covered, it can be hard to find it.

1.10.2. Docs

The qmail distribution includes a series of documents that are installed under /var/qmail/doc. They include:

These docs are also available on-line from:

1.10.3. FAQs

There are two official FAQ (Frequently Asked Questions, with answers) documents:

The web FAQ is more complete.

1.10.4. Books qmail

John Levine and Russell Nelson are writing a qmail book for O'Reilly & Associates ( which should be available later this year. Russell and John are frequent contributors to the qmail mailing list, and have demonstrated thorough knowledge of qmail and the ability to communicate it effectively and politely. O'Reilly has an excellent reputation in computing-related publishing. This book will undoubtedly become the qmail "bible".

For more information or to order this book when it becomes available, see Running qmail

Richard Blum has written Running qmail, which is published by Sams. This book has received mixed reviews on the qmail mailing list.

For more information or to order this book, see

1.10.5. List archives

The qmail e-mail mailing list, maintained by Dan Bernstein, is a valuable source of information. A web archive of the lists messages is kept at:

A search engine for the archive is at:

Other web archives are available at:

Most questions about qmail can be answered by searching the list archives first.

1.10.6. Other Web Sites

1.11. Support

1.11.1. Mailing lists

The following lists reside on In order to prevent harvesting of e-mail addresses by spammers, I'm avoiding the use of complete, valid addresses and "mailto" URL's.

The lists are managed by ezmlm, which uses different addresses to perform different functions:

To specify a subscription/unsubscription address, say, send the message to: qmail

The main qmail mailing list. Discussion and questions/answers on everything related to qmail, except serialmail. Read the FAQ and search the list archives before posting a question. When you ask questions, please try to include sufficient details to make it possible for people to respond: qmailannounce

The qmail announcement mailing list. New releases are announced here. There's no submission address: it's a read-only list. serialmail

For discussion of the serialmail package. ezmlm

For discussion of the ezmlm mailing list manager.

1.11.2. Consultants

See for a list of commercial support providers.

1.11.3. FAQTS Knowledgebase

A database of qmail-related questions and answers is available at If you have a question that the FAQ doesn't answer, try searching this knowledgebase. It's especially good at answering "how to" questions.

2. Installation

This section covers installing qmail. If you're an experienced system administrator, you can install qmail following the directions in INSTALL in the source distribution. The INSTALL directions are the official installation directions. They're more complex than the Life with qmail directions, and they assume that the reader is an experienced system and mail administrator.

Note: If you choose to install using the following directions, you should read through the entire section to familiarize yourself with the overall process.

2.1. Installation Issues

2.1.1. Binary vs. source code

Due to qmail's restrictive licensing regarding the distribution of prebuilt packages, qmail is usually installed from a source code distribution.

If you're not familiar with the distinction between source code and binaries, imagine ordering a pizza delivered to your house. The "binary" version of the pizza arrives ready-to-eat. The "source code" pizza comes as a kit containing flour, yeast, cheese, sauce, toppings, and directions for cooking the pizza yourself. Source code installations are a little more work for you, but if you follow the directions carefully, the result is the same--or even better. The self-baked pizza will be fresher, you can adjust the toppings to your preferences, and you'll know a lot more about your pizza and how it "works".

2.1.2. Tarball vs. OS-specific package

Some operating systems provide a mechanism for automating source code installations. Returning to the pizza analogy, they make it possible to package the ingredients and directions in such a way that you can just push a button and have the pizza bake itself.

Sounds great, doesn't it?

In practice, it might not be such a good idea. Assembling these packages is pretty difficult, and they might not do things the way they're supposed to. They're software, and like any software, they can have bugs. But even if they're bug free, the convenience they provide comes at a cost. You lose most of the advantages of the self-baked pizza: the ability to adjust the toppings to your personal preferences, and the knowledge of how the pizza was made and how it works.

If qmail was a pizza, the self-building approach might still be the way to go. But it's not: it's a fairly complicated system that the installer/maintainer needs to understand pretty well in order to be able to keep it working smoothly. The self-installing qmail is easier to install than the user-installed version, but the user-installed version is easier to configure and troubleshoot. You install qmail once on a system, but you will probably have several opportunities to reconfigure it or try to figure out why mail isn't flowing the way you think it should.

For this reason, I suggest installing qmail from scratch using the source code tarball, not a Red Hat "RPM" or other "self-installing" bundle.

2.2. Preparation

Before installing qmail on a system, especially if this is your first qmail installation, there are a few things you need to think about.

2.3. System requirements

qmail will install and run on most UNIX and UNIX-like systems, but there are few requirements:

2.4. Download the source

OK, so you've got a system meeting the requirements ready for installing qmail. The first step is to download the source code for qmail and any other add-ons. You'll need qmail, of course, and you should probably also get ucspi-tcp and daemontools:

Retrieve these files using your web browser or FTP client.

Note: If any of the links fail, it's probably because the package has been updated. In that case, you should go to and follow the links to download the current version. It's possible that upgraded versions aren't compatible with the following instructions, so be sure to read the release notes in the "Upgrading from previous versions..." sections.

2.5. Build the source

2.5.1. Verify build environment

The first thing you need to do is make sure that you have the necessary tools to compile a program. How you determine this depends on what flavor of UNIX you're using. The easiest way to tell, although it's not guaranteed, is to try it.

Note: if any one of these tests passes, you can stop and go on to the next section.

    $ cc

    cc: No input files specified


In this section we'll go through the actual steps of compiling qmail. A way to cut-n-paste will come in handy here, but isn't really necessary.

2.5.2. Unpack the distribution

If you made it this far, you have a working C compiler and copies of the tarballs. Copy or move the tarballs to the directory you want to do the work in. /usr/local/src is a good choice, and in this case you can use /usr/local/src/qmail for all three packages.

    mkdir -p /usr/local/src/qmail

    mv *.tar.gz /usr/local/src/qmail

You've got all three packages in /usr/local/src/qmail, so now you can unpack them. At this time you probably want to become root, if you're not already. At a prompt, type the following:

    su -

    cd /usr/local/src/qmail

    gunzip qmail-1.03.tar.gz

    tar xvf qmail-1.03.tar

    gunzip ucspi-tcp-0.88.tar.gz

    tar xvf ucspi-tcp-0.88.tar

    gunzip daemontools-0.70.tar.gz

    tar xvf daemontools-0.70.tar

    rm *.tar    # optional, unless space is very tight

There should now be subdirectories called qmail-1.03, ucspi-tcp-0.88, and daemontools-0.70. Change to the qmail-1.03 directory and let's get started:

    cd qmail-1.03

2.5.3. Create directories

Since qmail's installation program creates the subdirectories as they're needed, you only need to create the qmail "home" directory:

    mkdir /var/qmail

And on to the next section.

Note: If you want some or all of the qmail files to reside elsewhere than /var, this can be accomplished by creating symbolic links under /var/qmail pointing to the other locations.

For example, a more distributed layout can be achieved by doing:

    mkdir /var/qmail

    ln -s /usr/man /var/qmail/man

    mkdir /etc/qmail

    ln -s /etc/qmail /var/qmail/control

    ln -s /usr/sbin /var/qmail/bin

2.5.4. Create users and groups

The easiest way to create the necessary users and groups is to create a little script file to do it for you. In the source directory you'll find a file called INSTALL.ids. It contains the command lines for many platforms, so copying the file to another name and editing that is quick and easy.

    cp INSTALL.ids  IDS

Then, using your favorite editor, remove all of the file except the lines you want. For example, here's what IDS would look like for FreeBSD after editing:

    pw groupadd nofiles

    pw useradd alias -g nofiles -d /var/qmail/alias -s /nonexistent

    pw useradd qmaild -g nofiles -d /var/qmail -s /nonexistent

    pw useradd qmaill -g nofiles -d /var/qmail -s /nonexistent

    pw useradd qmailp -g nofiles -d /var/qmail -s /nonexistent

    pw groupadd qmail

    pw useradd qmailq -g qmail -d /var/qmail -s /nonexistent

    pw useradd qmailr -g qmail -d /var/qmail -s /nonexistent

    pw useradd qmails -g qmail -d /var/qmail -s /nonexistent

Then to run it, either use chmod to make it executable or run it with sh:

First method:

    chmod 700 IDS


Second method:

    /bin/sh IDS

When the script finishes, all of your users and groups will be created and you can go on to the next section.

But what do you do if your system isn't listed in INSTALL.ids? You'll have to create them manually. Start by using your favorite editor and editing /etc/group. You need to add the following two lines to the end of the file:



Note: Make sure that 2107 and 2108 aren't already used.

Next, using vipw (most systems have it, if not you'll need to use your editor again but this time on /etc/passwd) add these lines to the end of the file:








Note: Make sure 7790-7796 aren't already in use and that 2107 and 2108 are the same group ids you used above.

You don't specifically need to add any of these lines to the end of the file, that's just the easiest way to explain it here.

You're now ready to continue on to the next section.

2.5.5. Do the build

You're now ready to start building qmail.

In the Verify Build Environment section, you located your C compiler. If it's not called cc or the directory it resides in isn't in your PATH environment variable, you'll need to edit conf-cc and conf-ld. Say your compiler is gcc, and it's in your PATH. Simply edit conf-cc and conf-ld and replace "cc" with "gcc".

Now type the following:

    make setup check

After the build is complete, you'll need to do your post installation configuration. A couple of scripts are provided to make this job a lot easier.

If your DNS is configured properly, this script should be all you need at this point:


If, for some reason, config can't find your hostname in DNS, you'll have to run the config-fast script:

    ./config-fast the.full.hostname

For example, if your domain is and the hostname of your computer is dolphin, your config-fast line would look like this:


qmail is now installed on your system and is ready to be run! The next section will guide you through the steps of starting and testing qmail.

2.6. Install ucspi-tcp

Earlier, you unpacked the qmail, ucpsi-tcp, and daemontools tarballs. In our example, we unpacked them into /usr/local/src/qmail. Now change to the ucpsi-tcp directory:

    cd /usr/local/src/qmail/ucspi-tcp-0.88

In the Do the build section, if you modified conf-cc and conf-ld, you'll need to make the same changes in this directory.

Then do:


    make setup check

That's it. ucpsi-tcp is installed.

2.7. Install daemontools

Change to the daemontools build directory:

    cd /usr/local/src/qmail/daemontools-0.70

Once again, if you modified conf-cc and conf-ld during the qmail and ucspi-tcp builds, you'll need to make the same changes in this directory.

Then do:


    make setup check

Test the build by following the directions in

2.8. Start qmail

2.8.1. /var/qmail/rc

The /var/qmail/boot directory contains example qmail boot scripts for different configurations: /var/spool/mail vs. $HOME/Mailbox, using procmail or dot-forward, and various combinations of these. Feel free to examine these, but for our installation, we'll use the following:


# Using stdout for logging

# Using control/defaultdelivery from qmail-local to deliver messages by default

exec env - PATH="/var/qmail/bin:$PATH" \

qmail-start "`cat /var/qmail/control/defaultdelivery`"

Use your editor to create the above /var/qmail/rc, then execute these commands:

    chmod 755 /var/qmail/rc

    mkdir /var/log/qmail

At this point you need to decide the default delivery mode for messages that aren't delivered by a .qmail file. The following table outlines some common choices.

Mailbox format Name Location defaultdelivery Comments
mbox Mailbox $HOME ./Mailbox most common, works with most MUA's
maildir Maildir $HOME ./Maildir/ more reliable, less MUA support
mbox  username /var/spool/mail See INSTALL.vsm traditional UNIX mailbox

See INSTALL.mbox, INSTALL.maildir, and INSTALL.vsm for more information.

To select your default mailbox type, just enter the defaultdelivery value from the table into /var/qmail/control/defaultdelivery. E.g., to select the standard qmail Mailbox delivery, do:

    echo ./Mailbox >/var/qmail/control/defaultdelivery

Note: defaultdelivery isn't a standard qmail control file. It's a feature of the /var/qmail/rc file above.

2.8.2. System start-up files The qmail script

If you were to manually execute the /var/qmail/rc script, qmail would be partially started. But we want qmail started up automatically every time the system is booted and we want it shut down cleanly when the system is halted.

This is accomplished by creating a startup/shutdown script like the following:



export PATH

case "$1" in


    echo -n "Starting qmail: svscan"

    cd /var/qmail/supervise

    env - PATH="$PATH" svscan &

    echo $! > /var/run/

    echo "."



    echo -n "Stopping qmail: svscan"

    kill `cat /var/run/`

    echo -n " qmail"

    svc -dx /var/qmail/supervise/*

    echo -n " logging"

    svc -dx /var/qmail/supervise/*/log

    echo "."



    cd /var/qmail/supervise

    svstat * */log



    echo "Sending ALRM signal to qmail-send."

    svc -a /var/qmail/supervise/qmail-send







    echo "Sending HUP signal to qmail-send."

    svc -h /var/qmail/supervise/qmail-send



    echo "Pausing qmail-send"

    svc -p /var/qmail/supervise/qmail-send

    echo "Pausing qmail-smtpd"

    svc -p /var/qmail/supervise/qmail-smtpd



    echo "Continuing qmail-send"

    svc -c /var/qmail/supervise/qmail-send

    echo "Continuing qmail-smtpd"

    svc -c /var/qmail/supervise/qmail-smtpd



    echo "Restarting qmail:"

    echo "* Stopping qmail-smtpd."

    svc -d /var/qmail/supervise/qmail-smtpd

    echo "* Sending qmail-send SIGTERM and restarting."

    svc -t /var/qmail/supervise/qmail-send

    echo "* Restarting qmail-smtpd."

    svc -u /var/qmail/supervise/qmail-smtpd



    tcprules /etc/tcp.smtp.cdb /etc/tcp.smtp.tmp < /etc/tcp.smtp

    chmod 644 /etc/tcp.smtp*

    echo "Reloaded /etc/tcp.smtp."



    cat <<HELP

   stop -- stops mail service (smtp connections refused, nothing goes out)

  start -- starts mail service (smtp connection accepted, mail can go out)

  pause -- temporarily stops mail service (connections accepted, nothing leaves)

   cont -- continues paused mail service

   stat -- displays status of mail service

    cdb -- rebuild the tcpserver cdb file for smtp

restart -- stops and restarts smtp, sends qmail-send a TERM & restarts it

doqueue -- sends qmail-send ALRM, scheduling queued messages for delivery

 reload -- sends qmail-send HUP, rereading locals and virtualdomains

  queue -- shows status of queue

   alrm -- same as doqueue

    hup -- same as reload




    echo "Usage: $0 {start|stop|restart|doqueue|reload|stat|pause|cont|cdb|queue|help}"

    exit 1



exit 0

This script is also available via The ".exe" tricks the web server into thinking the script is an executable, which prevents it from converting the file to DOS format.

Note: If you find that qmail exits shortly after the system is rebooted, you can prefix the env command in the "start" section of the script with nohup. E.g.:

    nohup env - PATH="$PATH" svscan &

Create the script using your editor or by downloading it with your web browser, then install it into your system's init.d directory, which should be in one of the following locations:

Name the script qmail. You'll also need to link the script into a couple of "rc" directories. These directories are named like rcN.d, where N is the runlevel they apply to. The intricacies of the startup directory tree are beyond the scope of this document, so if these simplified instructions don't suffice, consult your system documentation. Your rc directories will probably be in one of:

To create the links, execute the following commands, replacing RCDIR with the location of your system's rc directories:

    ln -s ../init.d/qmail RCDIR/rc0.d/K30qmail

    ln -s ../init.d/qmail RCDIR/rc1.d/K30qmail

    ln -s ../init.d/qmail RCDIR/rc2.d/S80qmail

    ln -s ../init.d/qmail RCDIR/rc3.d/S80qmail

    ln -s ../init.d/qmail RCDIR/rc4.d/S80qmail

    ln -s ../init.d/qmail RCDIR/rc5.d/S80qmail

    ln -s ../init.d/qmail RCDIR/rc6.d/K30qmail

Note: the numbers in the previous step are highly system dependent, but somewhat flexible. If Sendmail is currently installed, running the command "find RCDIR -name "*sendmail" -print" will give you numbers that should work for your system.

Make the startup script executable and link it to a directory in your path:

    # substitute the correct location of your rc dir on the next two lines

    chmod 755 /etc/init.d/qmail

    ln -s /etc/init.d/qmail /usr/local/sbin The supervise scripts

Now create the supervise directories for the qmail services:

    mkdir -p /var/qmail/supervise/qmail-send/log

    mkdir -p /var/qmail/supervise/qmail-smtpd/log

    chmod +t /var/qmail/supervise/qmail-send

    chmod +t /var/qmail/supervise/qmail-smtpd

Create the /var/qmail/supervise/qmail-send/run file:


exec /var/qmail/rc

Create the /var/qmail/supervise/qmail-send/log/run file:


exec /usr/local/bin/setuidgid qmaill /usr/local/bin/multilog t /var/log/qmail

Create the /var/qmail/supervise/qmail-smtpd/run file:


QMAILDUID=`id -u qmaild`

NOFILESGID=`id -g qmaild`

MAXSMTPD=`cat /var/qmail/control/concurrencyincoming`

exec /usr/local/bin/softlimit -m 2000000 \

    /usr/local/bin/tcpserver -v -p -x /etc/tcp.smtp.cdb -c "$MAXSMTPD" \

        -u "$QMAILDUID" -g "$NOFILESGID" 0 smtp /var/qmail/bin/qmail-smtpd 2>&1

Note: concurrencyincoming isn't a standard qmail control file. It's a feature of the above script.

Note: Under Solaris, the normal id program won't work right in this script. Instead of id, use /usr/xpg4/bin/id, e.g.:

    QMAILDUID=`/usr/xpg4/bin/id -u qmaild`

    NOFILESGID=`/usr/xpg4/bin/id -g qmaild`

Note: the memory limit specified in the softlimit command may need to be raised depending upon your operating system and hardware platform. If attempts to connect to port 25 fail, or remote systems are unable to send you mail, try raising it to 3000000 or 4000000.

Create the concurrencyincoming control file:

    echo 20 > /var/qmail/control/concurrencyincoming

    chmod 644 /var/qmail/control/concurrencyincoming

Create the /var/qmail/supervise/qmail-smtpd/log/run file:


exec /usr/local/bin/setuidgid qmaill /usr/local/bin/multilog t /var/log/qmail/smtpd

Make the run files executable:

    chmod 755 /var/qmail/supervise/qmail-send/run

    chmod 755 /var/qmail/supervise/qmail-send/log/run

    chmod 755 /var/qmail/supervise/qmail-smtpd/run

    chmod 755 /var/qmail/supervise/qmail-smtpd/log/run

Then set up the log directories:

    mkdir -p /var/log/qmail/smtpd

    chown qmaill /var/log/qmail /var/log/qmail/smtpd SMTP Access Control

Allow the local host to inject mail via SMTP:

    echo '127.:allow,RELAYCLIENT=""' >>/etc/tcp.smtp

    /usr/local/sbin/qmail cdb

2.8.3. Stop and disable the installed MTA

Although it's possible to run both qmail and your existing MTA, which is probably Sendmail, simultaneously, I don't recommend it unless you know what you're doing. And, frankly, if you're reading this, you probably don't know what you're doing. :-)

If your existing MTA is Sendmail, you should be able to stop it by running the init.d script with the "stop" argument. E.g., one of these should work:

    /etc/init.d/sendmail stop

    /sbin/init.d/sendmail stop

    /etc/rc.d/init.d/sendmail stop

If you can't find an init.d/sendmail script, you can locate sendmail's PID using "ps -ef|grep sendmail" or "ps waux|grep sendmail" and stop it using:

    kill PID-of-sendmail

If your MTA isn't Sendmail, check its documentation for the correct shutdown procedure.

You should also consider removing the old MTA completely from the system. At least disable the init.d script so it doesn't try to start up again when the system is rebooted.

For Red Hat Linux, removing Sendmail can be accomplished by:

    rpm -e --nodeps sendmail

Lastly, replace any existing /usr/lib/sendmail with the qmail version:

    mv /usr/lib/sendmail /usr/lib/sendmail.old                  # ignore errors

    mv /usr/sbin/sendmail /usr/sbin/sendmail.old                # ignore errors

    chmod 0 /usr/lib/sendmail.old /usr/sbin/sendmail.old        # ignore errors

    ln -s /var/qmail/bin/sendmail /usr/lib

    ln -s /var/qmail/bin/sendmail /usr/sbin

We're this close to being able to start qmail. The last step is to create a couple system aliases.

2.8.4. Create System Aliases

There are three system aliases that should be created on all qmail installations:

Alias Purpose
postmaster RFC 821 required, points to the mail adminstrator (you)
mailer-daemon de facto standard recipient for some bounces
root redirects mail from privileged account to the system administrator

To create these aliases, decide where you want each of them to go (a local user or a remote address) and create and populate the appropriate .qmail files. For example, say local user dave is both the system and mail administrator:

    echo dave > /var/qmail/alias/.qmail-root

    echo dave > /var/qmail/alias/.qmail-postmaster

    ln -s .qmail-postmaster /var/qmail/alias/.qmail-mailer-daemon

    chmod 644 /var/qmail/alias/.qmail-root /var/qmail/alias/.qmail-postmaster

See INSTALL.alias for more details.

2.8.5. Start qmail

Finally, you can start qmail:

    /usr/local/sbin/qmail start

2.9. Test the Installation

qmail should now be running. Follow the instructions in TEST.deliver and TEST.receive to verify that it's working correctly. Note that using these instructions, logging will be accomplished by multilog, not splogger.

3. Configuration

You've got qmail installed, either from the recommended source tarball method, or one of the self-compiling packages. This section contains information the mail administrator or system administrator will need to configure qmail to make it work the way they want it to.

3.1. Configuration Files

All of qmail's system configuration files, with the exception of the .qmail files in ~alias, reside in /var/qmail/control. The qmail-control man page contains a table like the following:

Control Default Used by Purpose
badmailfrom none qmail-smtpd blacklisted From addresses
bouncefrom MAILER-DAEMON qmail-send username of bounce sender
bouncehost me qmail-send hostname of bounce sender
concurrencylocal 10 qmail-send max simultaneous local deliveries
concurrencyremote 20 qmail-send