Automatic protections for application proxy firewalls include which of the following?

• A. Protocol fidelity
• B. Header destruction
• C. Both A and B
• D. Neither A nor B

Answer: (C)

Application proxy firewalls operate at the application layer and inspect traffic as valid application data, which lets them automatically enforce how the protocol should be used and sanitize traffic for safety. Protocol fidelity means the proxy checks that the traffic conforms to the protocol’s rules—correct command sequences, valid header syntax, proper state transitions—so malformed or out-of-sequence messages are blocked before reaching the backend. Header destruction involves removing or sanitizing headers that could leak internal details or carry exploits, such as stripping server-related information or unnecessary cookies, to reduce the attack surface. Taken together, these automatic protections address both protocol abuse and information leakage, making both capabilities part of the automatic protections provided.