qmail
qmail is the name of an advanced level of mail transfer agent for the UNIX based operating systems.
17 Alternatives To qmail
Dovecot
Dovecot is an open source IMAP and POP3 email server for Linux/UNIX-like systems, written with…
Exim
Exim is a message transfer agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet.
G Suite
Google’s encompassing suite of cloud-based business apps.
Haraka
Open source SMTP server written in Node.js
IceWarp
IceWarp integrates all communication & collaboration features in one unified solution.
Kerio Connect
KerioConnect is a commercial mail and groupware server.
Knowmail
Email and messaging Artificial Intelligence engine
MDaemon Messaging Server
Low cost, easy to use Email Server software for virtual, on-premise, or hosted deployments for…
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.
MailEnable
MailEnable is a Windows based mail server and email server program that is packed with the state of the features and functions like antivirus and spam filtering system, webmail management system, cardDAV, CalDAV and much more.
PowerMTA
PowerMTA is an industrial-strength software for high-volume email delivery.
ProtonMail
Secure email with absolutely no compromises. Get your free encrypted email account today.
Zarafa
Open Source Collaboration, providing integration with your existing Linux mailserver, native mobile…
Zimbra
Zimbra is trusted by over 500 million users to increase productivity with a complete set of collaboration tools while maintaining total control over security and privacy.
Zimbra Collaboration Suite
Zimbra Collaboration is an open, secure collaboration tool for email, calendaring, tasks and more.
iRedMail
A fully fledged, free email server solution, an open source project (GPL v2).