As part of the contest we conducted recently, we got 160+ comments from the geeky readers who choose their favorite firewall.
Based on this data, the top spot goes to.. drum roll please..
iptables is a user space application program that does packet filtering, network address translation (NAT), and port address translation (PAT). iptables is for IPv4. ip6tables is for IPv6.
iptables needs kernel with ip_tables packet filter (including Linux kernel 2.4.x and 2.6.x). Using iptables you can view, add, remove or modify the rules in the packet filter ruleset.
Home page: http://www.netfilter.org
Author: Rusty Russell
Latest stable release: 1.4.6
2. IPCop