mailserver

This guide describes the installation and configuration of a mail system on Centos 5.1 with SELinux enabled for enhanced security. This system will be able to service HTTP, HTTPS, SMTP, TLS, SMTP-AUTH, IMAP, POP3 clients and is virtual enabled allowing more than one domain to be served from the system.

Fail2ban has been successfully used to protect SSH daemons, but this article talks about how you can use fail2ban to lessen the load of mailservers by blocking previously identified blacklisted IPs or relay access abuse. Howto is was written for Gentoo, but should easily be applied to any Linux distro.