I’ve played a lot with the different setup and systems for running a mailserver.
Well – to be honest – there’s actually as many Mailserver systems as there is users 🙂
After testing OpenSource Groupware through my education as datamatician, I’ve actually tried the most systems.
Best of all – Zimbra OpenSource Server – along with a license for Zextras – this actually works perfect for setting up a running emailserver with ActiveSync / exchange functions. I’ve setup this solution for several companies that’ll run this with full functions. Along I’ll recommand Zextras – because their support really is working, And well they have build the best freeware Mailserver using ActiveSync – There’s also the option of buying a a Zimbra Network Edition
I’ve allso created an install guide for Making a Linux Mailserver – Postfix/MySQL/Spamassassin/Clam-AV/Amavis/Dovecot/Squirrelmail on Apache. Build on Normal Debian Linux and manually installed all packages required.