What is the purpose of an application firewall?

• A. It encrypts all traffic automatically.
• B. It monitors and blocks communications of an application based on policy.
• C. It replaces the router in the network path.
• D. It provides VPN access only.

Answer: (B)

An application firewall focuses on what an application is trying to do and enforces rules for that specific application. It inspects traffic in the context of the application's protocol and intended actions, then allows or blocks those actions according to a defined policy. This means it can stop malicious or unwanted behavior within the application, such as unusual input, restricted feature calls, or inappropriate data access, while permitting legitimate usage. It’s not primarily about encrypting traffic, replacing a router, or providing VPN access, which is why those other descriptions don’t fit.