Anti-Spam SMTP Proxy Server implements multiple spam filters
Provides mechanisms for walking through any arbitrary PHP variable
SMTP email proxy and relay server
Universal server
Sync Outlook with Google, SOGo or any other CalDAV / CardDAV server
EasyMailer: Bulk Email/SMS Sender Using SMTP
Bubbles the simple, easy to use HTTP web server, browser controlled
Open source e-mail tracker made with Flask, setup & run in 10 minutes
Zentyal is a Linux Small Business Server
Installation, Configuration, and Automation tool set for Crypt Mining
Microsoft Exchange compatible server and client libraries