Atmail Email Server Alternatives

Web-based IMAP email client

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

Zimbra Collaboration is an open, secure collaboration tool for email, calendaring, tasks and more.

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

SquirrelMail is a standards-based webmail package written in PHP.

open-source

hMailServer is a free e-mail server for Microsoft Windows.

Horde Groupware is a free, enterprise ready, browser based collaboration suite.

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

PowerMTA is an industrial-strength software for high-volume email delivery.

Exim is a message transfer agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet.

EmailSuccess is an advanced MTA built to handle the most critical reliability, performance, security, and deliverability requirements.

Open-Xchange Server 6 is the most advanced Linux based Groupware solution f.