From HostThyself

Postfix is a mail server with a focus on security.

[edit] Install Postfix on CentOS 5

To install postfix on CentOS, use yum.

[edit] Postfix with Webmin, Virtualmin

Postfix works with Webmin and Virtualmin.

If on checking configuration of Virtualmin, there is an error, add the following to /etc/postfix/main.cf

virtual_alias_maps = hash:/etc/postfix/virtual

Browse to the Virtual Domains page in the Postfix module.

In the field labeled "Domain mapping lookup tables", switch the radio button from None to the text field, and in the text field, enter:

hash:/etc/postfix/virtual

[edit] Setup Postfix with SMTP Auth

• Postfix SMTP AUTH (and TLS) HOWTO
• Secure Virtual Mailserver HOWTO Postfix + OpenLDAP + Dovecot + Jamm + SASL + SquirrelMail
• PostFix with DoveCot Install Guide