If you want to look into security, postfix is an excellent example of a good security design. With postfix, the entire system can be hacked into, and the attacker still won't have admin rights.
-- Aly Dharshi aly dharshi uleth ca System Administrator Organization of Residence Students Servers University of Lethbridge
"A good speech is like a good dress that's short enough to be interesting and long enough to cover the subject"