Which of the following is not true about an application proxy firewall?

A.
Better performance than non-proxy firewalls

B.
Works on all seven layers

C.
Inspects data within the packet

D.
Exists only for a limited set of protocols

Explanation:
Firewalls that act in a proxy fashion must pass the packet up to the
proxy software on the firewall, thus degrading performance. This ability to work on
all layers of the packet, and even to be able to filter based on the data within a
packet is a key advantage of application proxy firewall.