CleanMail is a complete SMTP/POP3 email security solution that fights against spam and viruses. It works with any mail server like Microsoft Exchange 2003/2007/2010, Microsoft Small Business Server (SBS) 2003/2008, Lotus Notes/Domino, or IMail. CleanMail includes a comprehensive set of filters, including an attachment blocker, remote blacklist filter (DNSBL), and a complete build of SpamAssassin.
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.
HeaderCleaner is a small SMTP server plugin that will only allow a set of predefined headers in an outgoing email message and will strip all other headers from the message. This is meant to improve your privacy and better protect the mail handling server. This version is made for Communigate-Pro, but can be adapted for other systems.
Inbucket is an email testing service. It accepts messages for any email address and makes them available to view via a Web interface. It allows Web developers, software engineers, and system administrators to quickly see the emailed output of their applications. No per-account setup is required. Mailboxes are created on the fly as mail is received for them, and no password is required to browse the content of the mailboxes.
IndiMail is a messaging platform built using qmail and other messaging software. IndiMail has the ability to distribute the users in a domain across multiple hosts. IndiMail has multiple queues (called a queue collection), which can achiever very high concurrencies. The system IDs and configuration files used by IndiMail are all configurable through a set of environment variables, allowing you to customize IndiMail the way you want. IndiMail does not use hard-coded uid/gid in the executables, which makes it easy to distribute a binary package. IndiMail has features that any modern email server should have: SMTP, QMQP, QMTP, IMAP, POP3, DKIM, BATV, greylisting, filtering capability, and spam/virus control.
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.
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.
Melon MailServer is a simple mail server emulator for developers. It can emulate POP3 and SMTP services. The SMTP facility receives and stores all the messages sent to it rather than sending them. The POP3 facility allows you to download any messages without authorization. The server is designed to accept all messages for any email accounts. It can be very useful for testing Web applications and other software applications.