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.

An open source mailserver suite.

Web-based IMAP email client

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...

KerioConnect is a commercial mail and groupware server.

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.

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

Microsoft Office is an office suite of desktop applications, servers, and services for the Microsoft Windows and OS X operating systems.

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.