Issue TOC Print full article Print this page Download as PDF E-Mail this URL Discuss this article Flame the author     In this article Introduction Testing App-Level Firewalls Secure Computing Corp. Check Point Software Technologies FireWall-1 NG FP3 Other Products Reviewed Executive Summary How We Tested Glossary & Web Links Report Card

Glossary
• Application-level firewall: A proxy that examines network traffic at the application-protocol level and can enforce protocol syntax and filter specific protocol commands and content.
• Circuit-level gateway (also known as a proxy): A circuit-level gateway is similar to a stateful packet filter except the circuit-level gateway proxies connections passing through it. Clients and servers never communicate directly.
• Stateful packet-filtering firewall: A firewall that monitors TCP session state and drop/reject packets that are not part of a current session or are out of state with a current session. Application filtering is usually limited to handling randomly assigned connections within protocols like FTP or H.323.

Web Links
"Defense Starts Here" (Network Computing, Feb. 20, 2003)

"3Com Embeds Firewall in PC NICs" (Network Computing, Nov. 15, 2002)

"Dial 1-800 Plug Holes" (Network Computing, Nov. 1, 2002)

"Building an In-Depth Defense" (Network Computing, July 9, 2001)

"A Rookie's Guide to Defensive Blocks" (Network Computing, June 24, 2002)