[rrs@learner ~] cat SERVICES/Firewall | less

GNU/Linux has firewalling concept at the core of it's brain, The Kernel. The Linux Kernel 2.4.x series has excellent firewalling capabilities, NETFILTER, with rock solid stability and excellent security. IPTABLES, a part of the NETFILTER project is the base of firewalling under Linux 2.4.x

Features:-

• IP NAT
• IP Masquerade
• Packet Filtering
• PRE-ROUTING and POST-ROUTING
• Demilitarized Zones
• Port based firewalling
• Host based firewalling