Mailismus is a secure high-performance mail server, which incorporates SMTP, IMAP and POP3 servers. It is highly configurable, capable of performing multiple roles and is possibly the fastest single-instance mail server available.
It runs on any Unix/Linux, Windows or MacOS X platform and merely requires Java (Java 8 or later) to be installed.

Features include:

See the Admin Guide for the full details.
Mailismus is powered by the Network Application Framework (NAF).

Mailismus is free and open-source, distributed under the terms of the GNU Affero General Public License, version 3 (AGPLv3).

View MTA Queue View SMTP Grey-List
MTA-Queue screenshot GreyList screenshot

Some typical deployment scenarios to which Mailismus is suited are:

In addition to its performance and anti-spam measures, Mailismus is also distinguished by the depth and breadth of its logging options, providing for formal audit logs and exhaustive SMTP, IMAP and POP3 transcripts, in addition to the standard trace-level application logging you would normally expect.
Never again need you face the frustration of submitting messages into a black hole and wondering what happened to them and why.