Take back control of your email with this mail server in a box
A fast, highly extensible, and event driven SMTP server
Mail hosting made simple
Fast and easy-to-use webmail front-end for your existing mail server.
Zentyal is a Linux Small Business Server
A serverless email server on AWS using S3 and SES
Internet - Multi Server Control Panel
Easy installation and configuration of a complete mail server
an 'auto-reply' bot for your mail server
Webkosa is the open source edition of Webcrossing.
File scanning spam filter MDaemon plugin.