Dr. Hidaia Mahmood Alassouli - Creation of Postfix Mail Server Based on Virtual Users and Domains

By

Dr. Hidaia Mahmood Alassouli

Hidaia_alassouli@hotmail.com

Supervised by:

Dr. Hidaia Alassouli

Student Name

Khumalo, Khumbulani V.

It is common these days for a single system to host many domains, for example uniswa.com and mtn.com or acme .com may run on a single host machine, but behave as if they were on three different hosts. A system usually has a canonical domain, it has its usual or local domain name, and additional domains are configured as virtual domains.

The purpose behind this work is to create a mail server solution based on Postfix that is based on virtual users and domains, i..e. users and domains that are in a MySQL database. The goal is to have completely virtual users and domains. bob@uniswa.com != bob@acme.com. This means creating a separate name spaces for reach domain.

It will also demonstrate the installation and configuration of Courier-Imap (IMAP/POP3), so it can authenticate against the same MySQL database Postfix uses. The resulting postfix server is capable of quota which is not built into Postfix by default; the project will demonstrate how to patch postfix appropriately. Passwords are stored in encrypted form in the database. The work also covers the installation of Mail Scanner, SpamAssassin and ClamAv so that emails will be scanned for spams and viruses. The administration of MySQL database can be done through a web based tool Postfixadmin or can be done manually in the MySQL shell. Postfixadmin is a web based management tool created for Postfix that handles Postfix style virtual domains and users that are stored in MySQL. The squirrelmail web based email client is installed, in order to check emails from anywhere in world via internet. All installations were done in Fedora 5 Linux machine.

1. Introduction

2. Description of the Project

2.1 Main Objectives

2.2 System Overview

2.3 Main Server Components

3. Main installation and configuration of the mail server packages

3.1 Installing Postfix

3.2 Initial Configuration of Postfix

3.3 Installing MySQL packages

3.4 Creating MySQL Tables

3.5 Populating database with some data

3.6 Creating Postfix-MySQl Configuration Files

3.7 Creating Virtual User and Virtual Directory

3.8 Configuring Postfix with MySQL maps

3.9 Installing Courier-IMAP and Courier-authlib6

3.10 Courier-IMAP Configuration19

3.11 Configuring Postfixadmin

3.12 Configuring Squirrelmail

3.13 Installing and Configuring MailScanner, ClamAV and SpamAssassin

4 Testing the configuration

5 Conclusion

The purpose behind this project is to create a mail server solution based on Postfix that is based on virtual users and domains, i..e. users and domains that are in a MySQL database. It will also demonstrate the installation and configuration of Courier-Imap (IMAP/POP3), so it can authenticate against the same MySQL database Postfix uses. The resulting postfix server is capable of quota which is not built into Postfix by default; the project will demonstrate how to patch postfix appropriately. Passwords are stored in encrypted form in the database. The project also covers the installation of Mail Scanner, SpamAssassin and ClamAV so that emails will be scanned for spams and viruses. The administration of MySQL database can be done through a web based tool Postfixadmin or can be done manually in the MySQL shell. Postfixadmin is a web based management tool created for Postfix that handles Postfix style virtual domains and users that are stored in MySQL. The squirrelmail web based email client is installed, in order to check emails from anywhere in world via internet. All installations were done in Fedora 5 machine.

The project composed from the following parts:

• Installing Postfix.

• Installing Courier-IMAP (in case you want to use Courier as IMAP/POP Server).

• Creating the Database Tables.

• Populating Database with Some Data.

• Creating the Postfix-Mysql Configuration Files.

• Installing Postfixadmin.

• Installing MailScanner.

• Installing ClamAV and SpamAssassin.

• Creating the Virtual User and Virtual Directory.

• Configuring MailScanner.

• Configuring Postfix.

• Courier-IMAP Configuration.

• Configuring Squirrellmail.

• Testing the Configuration.

I advice that you install the necessary packages from rpm.pbone.net. All installations were done in Fedora 5 Linux machine.

2.1 Main Objectives:

The main objective of this work is to create an email server that supports mail delivery to multiple virtual domains .Each email address will be authentic to only that domain, for example Bob@mtn.com and Bob@acme.com are two different accounts that each receives different emails.

When the mail server setup has been completed it must be able to:

Receive and store emails for users.

Support quota to keep the mailboxes to a reasonable size of choice.

Let users retrieve emails through IMAP and POP3.

Receive and forward email for users if they are authenticated.

Offer a webmail interface to read emails in a web browser.

Detect virus and spam emails and filter them out or tag them.

2.2 System Overview:

The project describes how to create an email server with virtual domains and virtual users (users who can not log into the system, they can only exist in a database).

Basic knowledge of the following components is required to successfully set up the server.

MySQL (creating a database, granting access to users), this is a database system that stores information about the domains, the user accounts and email forwarding.

SMTP (Postfix) this is a protocol used between mail servers to send email messages.

POP3, IMAP the type used here is Courier-IMAP an alternative could be dovecot, this is a server that provides access to mail directories.

Fedora (Linux), understanding the general system administration, using text editor, command line and reading log files.

The accounts are stored in a MySQL database .The domains will have separate name spaces, for example mail for Bob@acme.com and Bob@mtn.com will go to separate mailboxes. So the arrangement will be separate mailboxes for each virtual account.

The server will use a POP/IMAP server that supports multiple domains. In this arrangement the administrator need not create and maintain system accounts for email addresses on the server, instead he will configure Postfix to deliver mail to a local message store where each virtual email address can have its own mailbox file. The users then retrieve their messages through the POP /IMAP server.

In addition the server will be capable of quota support and scanning of spam and viruses (Mail Scanner, Spam Assassin). The database (MySQL) will be managed manually from the command line mysql shell or by a web based management tool (Postfixadmin) created for postfix, and the users access their emails through a web based email client interface client (Squirrelmail).The block diagram below (figure 1) illustrates the system.