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 9.04)

Version 1.0
Author: Falko Timme

This tutorial is Copyright (c) 2009 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 Postfix mail server 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 9.04 Server (Jaunty Jackalope), so you should set up a basic Ubuntu 9.04 server installation before you continue with this tutorial (e.g. as shown on the pages 1 - 3 in this tutorial: The Perfect Server - Ubuntu Jaunty Jackalope (Ubuntu 9.04) [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 2.5.5 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 = 2.5.5
milter_macro_v = $mail_name $mail_version
[email protected]:/usr/src#


gunzip postfix-2.5.5-vda-ng.patch.gz
cd postfix-2.5.5
patch -p1 < ../postfix-2.5.5-vda-ng.patch

You might see a warning like this at the end of the dpkg-buildpackage command:

dpkg-buildpackage: warning: Failed to sign .dsc and .changes file

You can ignore this message.

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 5948
drwxr-xr-x 19 root root    4096 2009-05-26 15:56 postfix-2.5.5
-rw-r--r--  1 root src     3714 2009-05-26 15:59 postfix_2.5.5-1.1_amd64.changes
-rw-r--r--  1 root src  1305706 2009-05-26 15:59 postfix_2.5.5-1.1_amd64.deb
-rw-r--r--  1 root src   228581 2009-05-26 15:52 postfix_2.5.5-1.1.diff.gz
-rw-r--r--  1 root src     1178 2009-05-26 15:52 postfix_2.5.5-1.1.dsc
-rw-r--r--  1 root src  3157877 2008-09-03 17:04 postfix_2.5.5.orig.tar.gz
-rw-r--r--  1 root src    58389 2008-09-06 05:02 postfix-2.5.5-vda-ng.patch
-rw-r--r--  1 root src    41574 2009-05-26 15:59 postfix-cdb_2.5.5-1.1_amd64.deb
-rw-r--r--  1 root src   140916 2009-05-26 15:59 postfix-dev_2.5.5-1.1_all.deb
-rw-r--r--  1 root src   916552 2009-05-26 15:59 postfix-doc_2.5.5-1.1_all.deb
-rw-r--r--  1 root src    49688 2009-05-26 15:59 postfix-ldap_2.5.5-1.1_amd64.deb
-rw-r--r--  1 root src    43226 2009-05-26 15:59 postfix-mysql_2.5.5-1.1_amd64.deb
-rw-r--r--  1 root src    43302 2009-05-26 15:59 postfix-pcre_2.5.5-1.1_amd64.deb
-rw-r--r--  1 root src    43340 2009-05-26 15:59 postfix-pgsql_2.5.5-1.1_amd64.deb
[email protected]:/usr/src#

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

dpkg -i postfix_2.5.5-1.1_amd64.deb postfix-mysql_2.5.5-1.1_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: Antonio J. Delgado

One thinkg I do before this is to hold the postfix package. Thereby I use the command:

echo "postfix hold" | dpkg --set-selections

 And apt won't update postfix in the future and the quotas still working.

Nice tutorial.

By: Pascal

ERROR: Connection dropped by IMAP server

This is error that i got, and when i check log file :

 Sep 24 03:26:12 ser1 imapd: Connection, ip=[::1]
Sep 24 03:26:12 ser1 imapd: LOGIN FAILED, [email protected], ip=[::1]
Sep 24 03:26:17 ser1 imapd: LOGOUT, ip=[::1], rcvd=53, sent=332
Sep 24 03:26:34 ser1 imapd: Connection, ip=[::1]
Sep 24 03:26:34 ser1 imapd: LOGIN FAILED, [email protected], ip=[::1]
Sep 24 03:26:39 ser1 imapd: LOGOUT, ip=[::1], rcvd=53, sent=332
Sep 24 03:26:53 ser1 postfix/postfix-script[4679]: refreshing the Postfix mail system
Sep 24 03:26:53 ser1 postfix/master[4562]: reload configuration /etc/postfix
Sep 24 03:29:42 ser1 imapd: Connection, ip=[::1]
Sep 24 03:29:42 ser1 imapd: chdir No such file or directory
Sep 24 03:29:45 ser1 imapd: Connection, ip=[::1]
Sep 24 03:29:45 ser1 imapd: chdir No such file or directory
Sep 24 03:29:49 ser1 imapd: Connection, ip=[::1]
Sep 24 03:29:49 ser1 imapd: chdir No such file or directory
Sep 24 03:30:45 ser1 postfix/smtpd[4662]: timeout after END-OF-MESSAGE from localhost.localdomain[]
Sep 24 03:30:45 ser1 postfix/smtpd[4662]: disconnect from localhost.localdomain[]
Sep 24 03:51:46 ser1 imapd: Connection, ip=[::1]
Sep 24 03:53:07 ser1 imapd: Connection, ip=[::1]


Any idea for my problem ..

thanks anyway

By: xdanx

Hey mate, you need to send a mail first.

 you get Sep 24 03:29:45 ser1 imapd: chdir No such file or directory

because you didn't send a mail first . 


mailx [email protected] 



By: Anonymous

ERROR: Connection dropped by IMAP server

I want it very much, because i'am too.

By: Larry

I have been using this setup for my mail server and love it.   I have a problem that I have not been able to resolve and I was wondering if someone could help me out.   My server needs to have multiple IP addresses bound to one interface.   My problem is that postfix always wants to send mail using the highest IP address.  This behaviour will not work for my setup.  I have tried having Postfix bind to a specific address, but it breaks the ClamAV/Amasvisd.   Any suggestions on how I can work with this.