Email Security through Procmail (the Procmail Sanitizer) provides methods to sanitize email, removing obvious exploit attempts and disabling the channels through which exploits are delivered. Facilities for detecting and blocking Trojan Horse exploits and worms are also provided.
XamimeLT is an email scanner which encapsulates your existing sendmail or Postfix server setup. It scans both incoming and outgoing email. It can scan for email viruses, unwanted file types (eg. EXE, BMP, MPEG) and file names (eg. prettypark.exe), spam, and almost anything you care to search for in an email. It can also be used to scan for text snippets within emails and to insert disclaimers into outbound emails. XamimeLT was formerly known as "Inflex".
sn is a small news system for sites which serve perhaps a few dozen newsgroups, and which have a slow connection to the Internet. The target user is a home or SOHO with a single modem connection to the Internet and serving a few workstations. sn also includes a mail-to-news filter.
XCmail is a MIME and multi POP3 capable mailtool for X11 using the Xclasses X11 layout library. Its main purpose is to read and write mail, allowing any kind of data to be attached. It can handle MIME types, has helpers to show different types, and can encode and decode binary data into ASCII to allow it to be transported as mail over the Internet. It has many built-in functions such as 2 vCards, unlimited POP3 servers, SMTP, SMTP after POP3, SMTP-AUTH (RFC2554), addressbook, encoders, filters, a special spam filter, spell checker, xface, and a new "virtual folder" concept. It also uses external programs to enhance its feature set. XCmail can be extended through a plugin interface.