logwatch is a packet filter / firewall / IDS log analyzer written by Boris Wesslowski originally for RUS-CERT. It supports a lot of log formats and has many analysis options. It also features incident report and realtime response capabilities, an interactive web interface and internationalization. fwlogwatch is open source software under the GPL
FIRE|GATE is a Linux IPtables script for use as a firewall and
NAT/masquerade router for home networks or SOHO applications. It shares access to a single internet connection from multiple workstations, and can optionally forward all inbound HTTP, SMTP or other requests to internal servers (as opposed to a DMZ).
This software was previously hosted at http://www.lunarfox.com/netfilter.html which
was hijacked by BuyDomains/Seeq:com, with the help of RegisterFly.
Don't award them any traffic by using the old link! The new primary location is http://firegate.integralogic.com, with multiple mirrors available.
FieryFilter is an interactive desktop firewall for Linux. It will ask the user every time a new network connection is made if they want to allow or deny it. The user is able to generate rules from connections and thus minimize the amount of questions asked.
SmoothWall Express is an open source firewall distribution based on the GNU/Linux operating system.
SmoothWall is configured via a web-based GUI, and requires absolutely no knowledge of Linux to install or use.