Linux IP Firewalling Chains, normally called ipchains, is

free software Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, ...

to control the

packet filter In computing, a firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted network and an untrusted n ...

firewall Firewall may refer to: * Firewall (computing), a technological barrier designed to prevent unauthorized or unwanted communications between computer networks or hosts * Firewall (construction), a barrier inside a building, designed to limit the spre ...

capabilities in the 2.2 series of

Linux kernel The Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally authored in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU ...

s. It superseded

ipfirewall ipfirewall or ipfw is a FreeBSD Internet Protocol, IP, stateful firewall, packet filter and traffic accounting facility. Its ruleset logic is similar to many other packet filters except IPFilter. ipfw is authored and maintained by FreeBSD volu ...

(managed by ipfwadm command), but was replaced by iptables in the 2.4 series. Unlike iptables, ipchains is stateless. It is a rewrite of Linux's previous

IPv4 Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version d ...

. This newer ipchains was required to manage the

s starting with version 2.1.102 (which was a 2.2 development release). Patches are also available to add ipchains to 2.0 and earlier 2.1 series kernels. Improvements include larger maxima for packet

counting Counting is the process of determining the number of elements of a finite set of objects, i.e., determining the size of a set. The traditional way of counting consists of continually increasing a (mental or spoken) counter by a unit for every elem ...

, filtering for fragmented packets and a wider range of protocols, and the ability to match packets based on the inverse of a rule. The ipchains suite also included some shell scripts for easier maintenance and to emulate the behavior of the old ipfwadm command. The ipchains software was superseded by the iptables system in

2.4 and above.

References

External links

* IPChains HOWTO
on TLDP
an

{{Linux kernel Discontinued software Firewall software Free network-related software Free security software Free software programmed in C Linux kernel features Linux security software