SpamTestBuddy is a simple, light-weight, multiple-input spam scoring tool. It is standalone and can be used with simple procmail rules without root access or daemons. It features built-in support for simple DNS checks including DNSBL (DNS-based blocklist) queries, and can scan headers from filters such as SpamProbe, QSF, DSPAM. The configuration is flexible and easy to edit in a human readable file. Different tests can add or remove from the total score. You might think of SpamTestBuddy as a very light version of SpamAssassin.
Horde Groupware Webmail Edition is an enterprise ready browser-based communication suite. Users can read, send, and organize email messages and manage and share calendars, contacts, tasks, and notes with the standards compliant components from the Horde Project. It bundles the separately available applications IMP, Ingo, Kronolith, Turba, Nag, and Mnemo. It can be extended with any of the released Horde applications or the Horde modules that are still in development, like a file manager, a bookmark manager, a forum, or a wiki.
Imabluri takes a message from your SMTP server, runs virus and spam checks on it, and does some marking and logging. Afterwards, it hands the message over to your mailbox system or IMAP/POP3 server. A daemon approach minimizes the system load. A very small client program actually takes the mail from the SMTP server, writes it to your hard drive, and adds it to a MySQL database. The daemon is polled after the client stores the message, and tries to spawn a child process that does the actual checks. This project replaces vislog, which will no longer be mantained.
fdm (fetch and deliver mail) is a simple, lightweight replacement for mail fetching, filtering, and delivery programs such as fetchmail and procmail. It can fetch using POP3, POP3S, IMAP, IMAPS, or stdin, and deliver to a pipe, file, maildir, mbox, or SMTP server, based on a set of regexps. It can be used for both single user and multiuser setups, and is designed with privilege separation when running as root.