Arno's IPTABLES Firewall Script
Arno's Iptables firewall is a script which was originally derived from Seven's iptables script. One of the biggest differences is that this script also has support for ADSL modems. It also features stealth scan detection, extensive user-definable logging with rate limiting to prevent log flooding, masquerading and port forwarding (NAT), optimizing the throughput of your connection, protection against SYN/ICMP flooding, and much more. It's easy to configure and highly customizable. It includes a filter script (fwfilter) to make your firewall log more readable.