There was a “The ultimate OpenBSD email server” thread on misc@ those days. After “Mailserv”, another response was “iRedMail”. Still interested in the subject, here’s Yet Another Quick Review of the iRedMail 0.8.1 on OpenBSD 5.1.
Quoting its website: iRedMail is a ZERO COST, full-featured, Open Source Email Server Solution released under GPLv2. Woaw… You saw that great fireworks and garland lights… Just kidding. Now, let’s see what you get.