A Brief History of Linux Firewalling


Linux pre-2.2: ipfwadm
Port of ipfw.
Basic stateless firewalling.
ipautofw/ipportfw for reverse connections with Masquerading

Linux 2.2: ipchains
New, faster stateless firewall.
Allows the use of multiple rule chains to allow users to reduce the number of rules traversed on average.
Introduced ipmasqadm.