Postfix

Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail. It attempts to be fast, easy to administer, and secure. The software is also known by its former names VMailer and IBM Secure Mailer.

Free Open Source Mac OS X Linux

Exim

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

Free Open Source Mac OS X Windows Linux

Atmail Email Server

Atmail webmail system offers a webmail client, email server platform and mailserver appliance for Linux, Unix and Windows.

Commercial Linux Web

Courier-MTA

The Courier mail transfer agent (MTA) is an integrated mail/groupware server based on open commodity protocols, such as ESMTP, IMAP, POP3, LDAP, SSL, and HTTP.

Free Open Source Mac OS X Linux BSD Self-Hosted

Dragonfly Mail Agent

a small mail transport agent (mta), designed for home and office use. part of http://alternativein .

Free Open Source Linux BSD

Sendmail

Sendmail is a general purpose internetwork email routing facility that supports many kinds of transfer and delivery methods, including the Simple Mail Transfer Protocol (SMTP) used for email transport over the Internet.

Free Open Source Mac OS X Linux

OpenSMTPD

OpenSMTPD is a FREE implementation of the server-side SMTP protocol as defined by RFC 5321, with some additional standard extensions. It allows ordinary machines to...

Free Open Source Linux BSD Self-Hosted

Hectane

An SMTP client that is extremely easy to configure and use, providing a simple HTTP API that is used for sending emails.

Free Windows Linux

AtMail Open

AtMail is an open source webmail client written in PHP. We aim to provide a elegant Ajax webmail client for existing IMAP mailservers, with less bloat and a focus on an...

Free Open Source Web

sSMTP

sSMTP is a simple MTA to deliver mail from a computer to a mail server. sSMTP is simple and lightweight, there are no daemons or anything hogging up CPU; Just sSMTP....

Free Open Source Linux

BulkMTA

BulkMTA is Commercial Mail Server Similar to PowerMTA. IP Rotation, DKIM, Sender / Receiver Rate limiting

Commercial Mac OS X Windows Linux

ArgoSoft Mail Server

Powerful and simple SMTP/POP3/Finger server, with built in Web interface for accessing mail via Web browser. Supports security features, such as SMTP authentication. Has...

Freemium Windows