There is a new version of this tutorial available for Ubuntu 13.10 (Saucy Salamander).

Virtual Users And Domains With Postfix, Courier, MySQL And SquirrelMail (Ubuntu 10.04)

This tutorial is Copyright (c) 2010 by Falko Timme. It is derived from a tutorial from Christoph Haas which you can find at You are free to use this tutorial under the Creative Commons license 2.5 or any later version.

This document describes how to install a mail server based on Postfix that is based on virtual users and domains, i.e. users and domains that are in a MySQL database. I'll also demonstrate the installation and configuration of Courier (Courier-POP3, Courier-IMAP), so that Courier can authenticate against the same MySQL database Postfix uses.

The resulting Postfix server is capable of SMTP-AUTH and TLS and quota (quota is not built into Postfix by default, I'll show how to patch your Postfix appropriately). Passwords are stored in encrypted form in the database (most documents I found were dealing with plain text passwords which is a security risk). In addition to that, this tutorial covers the installation of Amavisd, SpamAssassin and ClamAV so that emails will be scanned for spam and viruses. I will also show how to install SquirrelMail as a webmail interface so that users can read and send emails and change their passwords.

The advantage of such a "virtual" setup (virtual users and domains in a MySQL database) is that it is far more performant than a setup that is based on "real" system users. With this virtual setup your mail server can handle thousands of domains and users. Besides, it is easier to administrate because you only have to deal with the MySQL database when you add new users/domains or edit existing ones. No more postmap commands to create db files, no more reloading of Postfix, etc. For the administration of the MySQL database you can use web based tools like phpMyAdmin which will also be installed in this howto. The third advantage is that users have an email address as user name (instead of a user name + an email address) which is easier to understand and keep in mind.

This howto is meant as a practical guide; it does not cover the theoretical backgrounds. They are treated in a lot of other documents in the web.

This document comes without warranty of any kind! I want to say that this is not the only way of setting up such a system. There are many ways of achieving this goal but this is the way I take. I do not issue any guarantee that this will work for you!


1 Preliminary Note

This tutorial is based on Ubuntu 10.04 Server (Lucid Lynx), so you should set up a basic Ubuntu 10.04 server installation before you continue with this tutorial (e.g. as shown on the pages 1 - 3 in this tutorial: The Perfect Server - Ubuntu Lucid Lynx (Ubuntu 10.04) [ISPConfig 2]). The system should have a static IP address. I use as my IP address in this tutorial and as the hostname.

Make sure that you are logged in as root (type in

sudo su

to become root), because we must run all the steps from this tutorial as root user.

It is very important that you make /bin/sh a symlink to /bin/bash...

dpkg-reconfigure dash

Install dash as /bin/sh? <-- No

... and that you disable AppArmor:

/etc/init.d/apparmor stop
update-rc.d -f apparmor remove
aptitude remove apparmor apparmor-utils


2 Install Postfix, Courier, Saslauthd, MySQL, phpMyAdmin

To install Postfix, Courier, Saslauthd, MySQL, and phpMyAdmin, we simply run

aptitude install postfix postfix-mysql postfix-doc mysql-client mysql-server courier-authdaemon courier-authlib-mysql courier-pop courier-pop-ssl courier-imap courier-imap-ssl postfix-tls libsasl2-2 libsasl2-modules libsasl2-modules-sql sasl2-bin libpam-mysql openssl phpmyadmin apache2 libapache2-mod-php5 php5 php5-mysql libpam-smbpass

You will be asked a few questions:

New password for the MySQL "root" user: <-- yourrootsqlpassword
Repeat password for the MySQL "root" user: <-- yourrootsqlpassword
Create directories for web-based administration? <-- No
General type of mail configuration: <-- Internet Site
System mail name: <--
SSL certificate required <-- Ok
Web server to reconfigure automatically: <-- apache2
Configure database for phpmyadmin with dbconfig-common? <-- No


3 Apply The Quota Patch To Postfix

We have to get the Postfix sources, patch it with the quota patch, build new Postfix .deb packages and install those .deb packages:

aptitude build-dep postfix

cd /usr/src
apt-get source postfix

(Make sure you use the correct Postfix version in the following commands. I have Postfix 2.7.0 installed. You can find out your Postfix version by running

 postconf -d | grep mail_version

The output should look like this:

[email protected]:/usr/src# postconf -d | grep mail_version
mail_version = 2.7.0
milter_macro_v = $mail_name $mail_version
[email protected]:/usr/src#


cd postfix-2.7.0
patch -p1 < ../postfix-vda-2.7.0.patch

Now we go one directory up, that's where the new .deb packages have been created:

cd ..

The command

ls -l

shows you the available packages:

[email protected]:/usr/src# ls -l
total 6396
drwxr-xr-x 24 root root    4096 2010-04-29 14:00 linux-headers-2.6.32-21
drwxr-xr-x  7 root root    4096 2010-04-29 14:00 linux-headers-2.6.32-21-server
drwxr-xr-x 19 root root    4096 2010-06-04 16:02 postfix-2.7.0
-rw-r--r--  1 root src     3700 2010-06-04 16:03 postfix_2.7.0-1_amd64.changes
-rw-r--r--  1 root src  1418996 2010-06-04 16:03 postfix_2.7.0-1_amd64.deb
-rw-r--r--  1 root src   240154 2010-06-04 16:00 postfix_2.7.0-1.diff.gz
-rw-r--r--  1 root src     1191 2010-06-04 16:00 postfix_2.7.0-1.dsc
-rw-r--r--  1 root src  3418064 2010-02-18 07:05 postfix_2.7.0.orig.tar.gz
-rw-r--r--  1 root src    42522 2010-06-04 16:03 postfix-cdb_2.7.0-1_amd64.deb
-rw-r--r--  1 root src   146842 2010-06-04 16:03 postfix-dev_2.7.0-1_all.deb
-rw-r--r--  1 root src   999490 2010-06-04 16:03 postfix-doc_2.7.0-1_all.deb
-rw-r--r--  1 root src    50142 2010-06-04 16:03 postfix-ldap_2.7.0-1_amd64.deb
-rw-r--r--  1 root src    44278 2010-06-04 16:03 postfix-mysql_2.7.0-1_amd64.deb
-rw-r--r--  1 root src    44304 2010-06-04 16:03 postfix-pcre_2.7.0-1_amd64.deb
-rw-r--r--  1 root src    44336 2010-06-04 16:03 postfix-pgsql_2.7.0-1_amd64.deb
-rw-r--r--  1 root src    59667 2010-03-03 09:32 postfix-vda-2.7.0.patch
[email protected]:/usr/src#

Pick the postfix and postfix-mysql packages and install them like this:

dpkg -i postfix_2.7.0-1_amd64.deb postfix-mysql_2.7.0-1_amd64.deb


4 Create The MySQL Database For Postfix/Courier

Now we create a database called mail:

mysqladmin -u root -p create mail

Next, we go to the MySQL shell:

mysql -u root -p

On the MySQL shell, we create the user mail_admin with the passwort mail_admin_password (replace it with your own password) who has SELECT,INSERT,UPDATE,DELETE privileges on the mail database. This user will be used by Postfix and Courier to connect to the mail database:

GRANT SELECT, INSERT, UPDATE, DELETE ON mail.* TO 'mail_admin'@'localhost' IDENTIFIED BY 'mail_admin_password';
GRANT SELECT, INSERT, UPDATE, DELETE ON mail.* TO 'mail_admin'@'localhost.localdomain' IDENTIFIED BY 'mail_admin_password';

Still on the MySQL shell, we create the tables needed by Postfix and Courier:

USE mail;

CREATE TABLE domains (
domain varchar(50) NOT NULL,
PRIMARY KEY (domain) )

CREATE TABLE forwardings (
source varchar(80) NOT NULL,
destination TEXT NOT NULL,
PRIMARY KEY (source) )

email varchar(80) NOT NULL,
password varchar(20) NOT NULL,
quota INT(10) DEFAULT '10485760',

CREATE TABLE transport (
domain varchar(128) NOT NULL default '',
transport varchar(128) NOT NULL default '',
UNIQUE KEY domain (domain)


As you may have noticed, with the quit; command we have left the MySQL shell and are back on the Linux shell.

The domains table will store each virtual domain that Postfix should receive emails for (e.g.


The forwardings table is for aliasing one email address to another, e.g. forward emails for [email protected] to [email protected].

source destination
[email protected] [email protected]

The users table stores all virtual users (i.e. email addresses, because the email address and user name is the same) and passwords (in encrypted form!) and a quota value for each mail box (in this example the default value is 10485760 bytes which means 10MB).

email password quota
[email protected] No9.E4skNvGa. ("secret" in encrypted form) 10485760

The transport table is optional, it is for advanced users. It allows to forward mails for single users, whole domains or all mails to another server. For example,

domain transport smtp:[]

would forward all emails for via the smtp protocol to the server with the IP address (the square brackets [] mean "do not make a lookup of the MX DNS record" (which makes sense for IP addresses...). If you use a fully qualified domain name (FQDN) instead you would not use the square brackets.).

BTW, (I'm assuming that the IP address of your mail server system is you can access phpMyAdmin over in a browser and log in as mail_admin. Then you can have a look at the database. Later on you can use phpMyAdmin to administrate your mail server.

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5 Comment(s)

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By: Rick Stanley

I wish people would stop tagging every posting with Ubuntu! Most of the postings involved with the installation and configuration of software I have seen tagged with "Ubuntu" can also be done with MANY different Distros, including this one! You would think that there is only ONE Distro available! NOT!!!

Take a look at the top ten Distributions: DistroWatch

By: Anonymous

Did you not notice that distro-specific how-to's are what's created here for some topics? Calm down. This article, and in fact no post on this site claims Ubuntu is the end-all of linux.

By: Mohamed Elsayed

Dear Falko:

 many thanks for this great effort; actually I have installed my mail server before based on Christoph Haas tutorial at it was very helpful, and works 100%.

but for my need, there was something missing which is the mailing lists; I wanted to integrate mailman or any of mailing list management SW to be able to create mailing lists (for example [email protected]) and add the sales users to this list.

it will be perfect if you could complete this part in your great  tutorial which is (as I think) is very important for a many people.

I sent a comment like this to Christoph Haas on and I noticed that another people also were interested to add this feature to their implementation. 


thanks again for you and I hope you can find a time to complete it soon.



you could use the forward table, create a user and add all the emails to it

example: create user [email protected]

and add  the users [email protected]

                               [email protected]

and etc, this would be all done in the sql table forwards

I would use phpadmin much easier


I follow this,and the tables like this:

mysql> select * from forwardings;
| source           | destination                      |
|     | [email protected]                 |
| [email protected] | [email protected],[email protected] |
 then i sent a email to [email protected], only test usr can receive this email. but when i sent a email to a invalid user,eric user can receive a email.

Anyone can help me?