AMaViS (A Mail Virus Scanner) scans e-mail attachments for viruses using third-party virus scanners available for UNIX environments. It resides on a UNIX (Linux) machine and looks through the attached files arriving via e-mail, generates reports when a virus is found and sets the delivery on hold.
BlackMail is an Anti-Spam mailer proxy for use with popular MTA's like Sendmail, QMail, and SMail. It is highly configurable, very powerful, very fast, and runs on a large variety of platforms. It has undergone extensive testing, and this is the most stable release, now with Solaris support.
chpp is a general purpose preprocessor. It was designed originally for the purpose of preprocessing HTML code but can be used successfully in other fields of application as well. Highlights are, beside powerful language constructs, CGI-scripting support and an SQL database interface.
Deliver is a program for reliable and flexible local mail delivery. It's a perfect adjunct to your mail transport agent of choice (such as Sendmail or qmail). You can use it to kill spam, drop messages from specific senders, add a [LISTNAME] prefix to the subjects of messages that are delivered through mailing lists, and lots more.
The Download Slave is a very flexible script which is controlled via eMail and stores files requested for downloading on the server's harddisk or sends them via eMail to the user who asked for them. Users are identified by their eMail address and a personal password, so only authorized users can use the service.