An iptables IPv4 firewall and traffic shaping program
blocklists for openbsd,freebsd,linux,iptables,bsd pf,pf,ipfilter
Programmable completion code (bash) for ip[6]tables (netfilter.org)
Programmable completion code (bash) for ipset (netfilter.org)
HardWall Firewall for Linux 2.4/2.6