Systems Security Certified Practitioner – SSCP – Question0893

Application Layer Firewalls operate at the:

A. OSI protocol Layer seven, the Application Layer.
B. OSI protocol Layer six, the Presentation Layer.
C. OSI protocol Layer five, the Session Layer.
D. OSI protocol Layer four, the Transport Layer.

Correct Answer: A

Explanation:

Since the application layer firewall makes decisions based on application-layer information in the packet, it operates at the application layer of the OSI stack.
“OSI protocol layer 6, the presentation layer” is incorrect. The application layer firewall must have access to the application layer information in the packet and therefore operates at the application layer.
“OSI protocol layer 5, the session layer” is incorrect. The application layer firewall must have access to the application layer information in the packet and therefore operates at the application layer.
“OSI protocol layer 4, the transport layer” is incorrect. The application layer firewall must have access to the application layer information in the packet and therefore operates at the application layer.
References: CBK, p. 467 AIO3, pp.488 -490