10 Free Mail Servers

hMailServer

A free e-mail server for Microsoft Windows. It's used by Internet service providers, companies, governments, schools and enthusiasts in all parts of the world. It supports the common e-mail protocols (IMAP, SMTP and POP3) and can easily be integrated with many existing web mail systems. It has flexible score-based spam protection and can attach to your virus scanner to scan all incoming and outgoing email.Download

Java Apache Mail Enterprise Server

An open source SMTP and POP3 mail transfer agent and NNTP news server written entirely in Java. IMAP support has been added as of preview version 3.0-M2, which now requires Java 1.5 or later.Download

Courier Mail Transfer Agent

An integrated mail/groupware server based on open commodity protocols such as ESMTP, IMAP, POP3, LDAP, SSL, and HTTP. Courier provides ESMTP, IMAP, POP3, Webmail, calendaring, and mailing list services.Download

Zimbra

An open source server and client technology for next-generation enterprise messaging and collaboration. Download

Dwarf Mail Server 1.1.3

It implements SMTP, POP3 and IMAP4 rev1 protocols. It provides support for rich application message processing via pluggable mail filters and agents, as well as full handling of virtual domains for the SMTP/POP3/IMAP4 protocols.
Since the server is based on the Dwarf framework, it also shares its common design principles and features - simplicity, high modularity and extensibility, authentication and authorization, XML-based configuration, logging and remote management. Download

MailEnable Standard Edition

It provides robust SMTP, POP3 and web mail services for Microsoft Windows servers. Simple to install, with a powerful administration software means that your mail server will be up and running quickly. This edition is FREE, contains no spyware or adware, for both personal and commercial usage, with no time or user restrictions. Download

iRedMail

A free, full-featured mail server solution. All used packages are free and open source, provided by the Linux/BSD distribution vendors you can trust. It has been released under GPL v2 and is hosted on BitBucket. Download

Hedwig Mail server

An open source IMAP, SMTP server written in Java, designed with ease of installation and configuration in mind. Hedwig enables storage of mail message headers in a relational database (MySQL) and mail messages in a file system. Download

MachiNET Mailserver

Machinet mailserver is primarily meant for a small enterprise mail server using standard GPL components. Download

QMAIL 3.0.5

A communications program for mobile devices which supports POP3, IMAP4, NNTP & RSS protocols. The installation is simple and only involves copying the files to the Windows Mobile device. Download