Linux.com: Deploying a Linux FirewallOct 08, 1999, 17:38 (1 Talkback[s])
(Other stories by Jason Tackaberry)
"Many years ago, large, brick walls were erected between buildings and wood houses, so that if a fire broke out, it wouldn't spread. Naturally, these walls were called firewalls."
"The Internet is said to have connected somewhere around 50,000 networks, and over 200 million hosts. Unfortunately, some of these hosts are bound to have malicious users, or crackers. These days, a virtual firewall of sorts is constructed between the local network and the Internet to prevent the "fire" (the crackers) from spreading into the "building" (the local area network)."
"The firewall is typically the first line of defense for any Internet-connected network. Unfortunately, many network administrators take firewalls for granted, and they become not only their first but their last line of defense. It can't be stressed enough that firewalls are not the be all and end all of network security. While a well-constructed firewall policy will greatly reduce your susceptibility to attack, it will not (and cannot) completely eliminate it."