Maia Mailguard is an open source solution for managing spam and malware on Unix-based servers. Built atop a base of solid open source tools such as Postfix, SpamAssassin, amavisd-new, Clam Antivirus, MySQL, PostgreSQL, and apache, Maia Mailguard adds a web-based quarantine management system that lets administrators and end users configure their own mail filters and review any items that have been quarantined on their behalf. User feedback automatically trains the spam filter, resulting in a mail system that almost runs itself.

Visit the Maia Mailguard website for more details.