The Postfix Policyd plugin fights spam using techniques such as greylisting, source detection, volume measurements, blacklisting, and HELO rotation detection.

After penetrating a remote system, intruders might think they are home and dry, but AppArmor spoils the fun, locking the miscreants in a virtual cage.

Many tools keep growing with each new version, but Nmap 4.00 has lost weight thanks to the Diet-Nmap project. The latest incarnation of Nmap is not only quicker, it is also more frugal with memory.

Webalizer is a tool for analyzing web server logfiles. A new patch lets admins see what isn’t there.

If you need a tool for filtering protocols that doesn’t depend on the port, try L7, an IPTables patch that operates through regular expressions.