ABSTRACT
The current state of insecurity in which we find ourselves today calls for a careful review of the basics of firewall architectures.
The level of protection that any firewall is able to provide in securing a private network when connected to the public Internet is directly related to the architectures chosen for the firewall by the respective vendor. Generally speaking, most commercially available firewalls utilize one or more of the following firewall architectures:
• Static packet filter • Dynamic (stateful) packet filter • Circuit-level gateway • Application-level gateway (proxy) • Stateful inspection
• Cutoff proxy • Air gap
EXHIBIT 49.1 Firewall architectures.
