For inexperienced or impatient admins!
Five complete solutions for rapidly deploy a complete mail server with a single installation. Enjoy!
Citadel: Versatile and powerful mail server, written in C.
iRedMail: Mail server solution based on Postfix and Dovecot.
Mailcow: Mail server suite based on Dovecot, Postfix and other open source software. Provides a PHP Web UI for administration.
Mail-in-a-Box: Shell script that turns Ubuntu into a fully functional mail server.
Modoboa: Mail hosting and management platform with web interface, written in Python.