GNU Anubis is an SMTP message submission daemon. It represents an intermediate layer between the mail user agent (MUA) and mail transport agent (MTA), receiving messages from the MUA, applying to them a set of predefined changes, and finally inserting modified messages into an MTA routing network. The set of changes applied to a message is configurable on a system-wide and per-user basis. The built-in configuration language used for defining sets of changes allows for considerable flexibility and is easily extensible.
rjmailer is a replacement for the SMTP part of Sun's javamail library. It sends email messages via SMTP and has the ability to connect directly to the receiving mail servers instead of using a relay server, which in many cases can result in more detailed information about the delivery status.
Kordil EDMS is a powerful and user friendly electronic document management software. It is utilized with a power-tool that collects all the files of your organization under a single meeting point. It can manage data files, daily progress reports, daily information flow for your business, lessons learned, and several other kinds of information that may all be buried in a several Excel worksheets, email boxes, and personnel memories.
Mireka is a mail server with SMTP, Mail Submission, and POP3 services. It can also be used as an SMTP proxy. As a proxy, it can help to prevent or diagnose mail problems, like outgoing backscatter spam. It provides detailed logging, basic mail traffic statistics, tarpit to prevent email harvesting, and loop detection. It can filter email by DNSBL, SPF, mail size, local domains, and recipients list. Local recipients can be specified using regular expressions. TLS is supported for incoming connections. Aliases, forward lists, and very simple mailing lists can be configured in XML. Custom filters and other components can be written in Java, and they can be easily implemented and installed.
Lamson is an SMTP server adopts a modern Web application framework design. Rather than bizarre flat file "databases" and hashtable stores, Lamson uses anything that Python does to store data, including Django's ORM, web.py's simple database library, Tokyo Tyrant, Lightcloud, Python's Shelve (not recommended), Raw SQLite3, SQLObject, CouchDB, Mongo DB, and SQLAlchemy.
Masqmail is an MTA (mail transport agent) for notebooks, workstations, home servers, and generally any host with no permanent network connection. It has special support for multiple transfer routes (e.g. to different mail providers). Address rewriting can be done in several ways. It is a slim replacement for full-blown MTAs such as sendmail, exim, qmail, or postfix and for the intended uses, configuration is much simpler.