This document discusses the history and types of firewalls. It describes early circuit-level firewalls developed at AT&T and DEC in the 1980s. Packet filtering firewalls screening network traffic based on IP and TCP/UDP headers were introduced by Cisco in the early 1990s. Application layer firewalls called proxy firewalls were developed in the late 1990s, screening traffic based on application protocols like HTTP, FTP, and SMTP. The document also discusses stateful packet inspection, demilitarized zones (DMZs), and common firewall threats.
4. 5
DEC
8
AT&T Bell Laboratories
.
. SEAL
"SEAL"
Cisco
2
Packet Filtering Firewalls
Cisco
4
Jeff Mogul
5
Digital Equipment Corporation
6
Dave Presetto
7
Howard Trickey
3
8
9
circuit level firewalls
Bill Cheswick
11
Marcus Ranum
12
Gene Spafford
13
Application Layer Firewalls
14
Proxy-Based Firewalls
15
Bob Braden
16
Annette DeSchlon
17
Visas
18
Visual Integration
19
Check Point Software
20
Scott Wiegel
21
Global Internet Software Group
22
Kernel Proxy architecture
10
DEC