The Falcon Project (Free Application-Level CONnection kit) is an open firewall project with the intention of developing a free, secure and OS-independent firewall system. Falcon consists of three major modules: Falcons's own proxies (written in Perl); 3rd-party proxies (squid / qmail / BIND8), each modified for chroot environment; and general concepts for OS hardening, chrooting etc.
Astaro Portscan Detection is a netfilter target which will attempt to detect TCP and UDP port scans and log them to syslog. This target is based upon Solar Designer's scanlogd. It suppports mutliple levels of logging, custom prefixes for entries, weighted total port scan detection, and port scan temporal spread detection.
XOTcl provides a highly flexible, reflective, component-based object oriented environment that integrates language support for high level object oriented concepts (which are not found in other languages) with reasonable performance. XOTcl is an extension of TCL and was derived from the impressive OTcl language developed by D. Wetherall and C. Lindblad at MIT in 1995 and extended in various ways. XOTcl's language constructs explicitly aim at the complexity in a component gluing layer that is not solved by traditional object orientation in the style of C++ or Java.
FrazierWall Linux is a single floppy distribution Linux firewall that is based on the Linux Router Project. It is designed for use with ethernet base internet connections (such as cable modems or xDSL lines). It allows you to share such a connection with several other computers on a LAN. It is easy to setup and maintain, and is available in a Linux configurable software version.