Linux Firewall Software

A firewall on Linux does not need to be installed so much as it needs to be activated. Linux has a feature called IP Masquerading built in that can allow the operating system to act as a NAT firewall and router for your entire network. NAT allows all the computers on your LAN to access the internet through a single Internet registered IP address on your Linux computer.

Linux supports packet filtering. A packter filtering personal firewall can check the packet type, source address, destination address, and port information to ensure all data packets follow a rule set. This is a very powerful type of firewall that is very transparent to the users on your LAN.. Here are a list of resources to help you configure your Linux computer as a firewall.

Linux Firewall and Security Site

http://www.cotse.com/tools/firewall.htm

Firewall and Proxy Server HOWTO

http://en.tldp.org/HOWTO/Firewall-HOWTO.html

Linux IP Masquerading Web Site

http://www.indyramp.com/masq/

Linux IP Masquerade HOWTO

http://tldp.org/HOWTO/IP-Masquerade-HOWTO/

Internet Firewalls: Frequently Asked Questions

http://www.interhack.net/pubs/fwfaq/

There is also a movement on the Internet that is creating �micro� distributions of Linux with all the firewall protection capabilities built in. These micro-distributions can be run from a single 1.4Mb floppy disk and do not require a hard drive! A simple 486 with two NIC�s and a floppy drive is usually all that is required. Some of these firewalls can even be created and setup under Windows so no Linux knowledge is necessary & can place all of your computers behind a firewall. 

Smoothwall GPL - configure through browser!

Linux Router Project

http://www.linuxrouter.org/

Cyote Linux

http://www.coyotelinux.com/

For NetBSD Fans, The NetBSD/i386 Firewall Projects

http://www.bsdrouter.org/