Postfix - Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail.

Mocana Atlas Platform - Mocana creates and develops mobile application protection (MAP) app-shielding solutions, enabling users to secure mobile apps

mailcow - An open source mailserver suite.

ZingBox - ZingBox provides real-time IoT security solution to protect from cyber and insider threats.

Mail-in-a-box - Mail-in-a-Box provides webmail and an IMAP/SMTP server for use with mobile devices and desktop mail software and also includes contacts and calendar synchronization.

Bastille - Bastille provides comprehensive visibility and threat detection for IoT devices.