Linux Mail Server Setup and Howto Guide

This guide will show you how to setup an email server accessible using a POP3, IMAP or web browser client. It will also show you how to include virus scanning and spam tagging in the mail server. If you have an existing Active Directory or LDAP infrastructure, the last section will show you how to integrate it into your email server so you won’t have to maintain two sets of user accounts.

How to install Linux

You can use either Red Hat Enterprise Linux 5 or CentOS 5. RHEL 5 can be purchased from Red Hat and comes with support. CentOS 5 on the other hand can be downloaded here.

1. How to install CentOS 5.

2. How to setup CentOS 5.

To simplify our administration tasks, log in as the user root and specify your root password. This is not the recommended way of administering a Linux box, but for the tasks at hand it is the most efficient way.

How to install SMTP, POP3, IMAP and Webmail service

Postfix will be providing the SMTP service, Dovecot will provide the POP3 and IMAP service, while Apache and SquirrelMail will provide the Webmail service.

1. How to install and setup Postfix SMTP server.

2. How to install and setup Dovecot POP3 and IMAP server.

3. Configure Postfix SMTP Authentication using Dovecot SASL.

4. How to install and setup SquirrelMail WebMail.

5. How to configure the firewall.

How to create mailboxes, aliases and distribution groups

To create a mailbox, just create a new user account.

How to setup a mailing list or proxy address in Postfix.

How to add antivirus and antispam filtering

We will be using Clam AntiVirus for virus scanning, SpamAssassin for the spam tagging and MailScanner to integrate them into Postfix.

1. How to install MailScanner.

2. How to install Clam AntiVirus (ClamAV).

3. MailScanner, ClamAV, SpamAssassin and Postfix Integration Guide.

You can greatly reduce the volume of spam and viruses reaching your mail server if you are willing to give up something. If you are willing to have your mail delayed (time), install Postgrey. If you are willing to spend (money), get the Barracuda Spam Firewall.

How to integrate Active Directory/LDAP

Integrating Active Directory/LDAP into your mail server will turn your Linux email server into a lean and mean Exchange like machine. And you won’t have to deal with Linux system accounts or edit configuration files for common tasks like creating mailboxes and mailing lists. And finally, you can provide your users with standard address book.

Active Directory/LDAP virtual users in Postfix and Dovecot.

How to use the Active Directory Distribution Group in Postfix.

How to add Active Directory/LDAP into the SquirrelMail Addressbook.

Using Winbind to integrate Active Directory user accounts.
Another way to integrate Active Directory into your mail server. I highly recommend using the virtual user solution above instead of this one.

Webmin is a web-based interface for system administration for Unix. Using any modern web browser, you can setup user accounts, Apache, DNS, file sharing and much more. This page will show you how to install Webmin.

Fedora Directory Server is an enterprise-class open source LDAP server for Linux. This page will show you how to setup the Fedora Directory Server.

This page will show you how to install the Java Runtime Environment (JRE) from Sun Microsystem which is required by some applications like the JXplorer LDAP Browser and the Fedora Directory Server Administration tools.

This page will show you how to configure the ldap-chpasswd included in the SquirrelMail Change Password plugin. The ldap-chpasswd can change an LDAP server password. If you have not yet installed this plugin, see the SquirrelMail Change Password Howto.

This page will show you how to configure the ldap-chpasswd included in the SquirrelMail Change Password plugin. The ldap-chpasswd can change an Active Directory or LDAP server password. If you have not yet installed this plugin, see the SquirrelMail Change Password Howto.

To communicate with the Active Directory server over the Secure Sockets Layer (SSL), you need an SSL enabled server and an SSL certificate for the client. SSL communication is required to programmatically change the Active Directory password. This page will show you how to export an SSL certificate from an SSL enabled Windows Server 2003 to use the LDAP API over SSL. If you have not yet configured SSL, see Enable LDAP SSL with Active Directory.

SSL communication is required to programmatically change the Active Directory password using LDAP. This page will show you how to install the Certificate Services to enable LDAP SSL in Active Directory.

The SquirrelMail Change_passwd plugin, originally written by Thiago Melo de Paula, allows users to change his/her system password in /etc/passwd or /etc/shadow from SquirrelMail. This updated version includes the ability to change Active Directory and LDAP passwords.

Shows how to install the CAPTCHA SquirrelMail plugin by Paul Lesniewski. A CAPTCHA input is placed on the login screen to detect whether or not a human is attempting to log in. CAPTCHA stands for Completely Automated Public Turing to tell Computers from Humans Apart. It helps prevent automated login attacks.