hMail Server Alternatives

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.

A fully fledged, free email server solution, an open source project (GPL v2).

Microsoft Exchange Server is a messaging and collaborative software product developed by Microsoft.

Web-based IMAP email client

An open source mailserver suite.

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

Low cost, easy to use Email Server software for virtual, on-premise, or hosted deployments for...

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.

Axigen is an integrated email, calendaring & collaboration platform, built on a Linux mail server technology.

KerioConnect is a commercial mail and groupware server.

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.

Google's encompassing suite of cloud-based business apps.

Dovecot is an open source IMAP and POP3 email server for Linux/UNIX-like systems, written with...