Linux Firewalls, Third Edition

iptables: The Linux Firewall Administration Program

This book is based on the 2.6 Linux kernel series, though much of it is applicable to the 2.4 kernel series as well. Most distributions of Linux come supplied with the Netfilter firewall mechanism introduced in Chapter 3, “iptables: The Linux Firewall Administration Program.” This mechanism is usually referred to as iptables, its administration program's name. Older Linux distributions used the earlier IPFW mechanism. That firewall mechanism is usually referred to as ipfwadm or ipchains, the earlier version's administration program names.

iptables includes compatibility modules for both ipchains and ipfwadm. Some people might want to use one of these modules until their conversion to iptables ...