"firewall builder for Linux ... easy to use, audit, and understand. It allows you to create very readable configurations even for complex stateful firewalls. ... Sanewall is a fork of FireHOL."
"Transparent proxy server that works as a poor man's VPN. Forwards over ssh. Doesn't require admin. Works with Linux and MacOS. Supports DNS tunneling."
Up-to-date list of ad server hostnames and IP addresses in various formats
Configuration changes unfortunately require re-compilation, otherwise neat.
German abstract: http://linuxwochenende2010.luga.at/12/