Which of the following firewalls inspects the actual contents of packets?

The application level firewall inspects the contents of packets, rather than the source/destination or connection between the two. An Application level firewall operates at the application layer of the OSI model. Answer: A is incorrect. The circuit-level firewall regulates traffic based on whether or not a trusted connection has been established. It operates at the session layer of the OSI model. Answer: C is incorrect. The packet filtering firewall filters traffic based on the headers. It operates at the network layer of the OSI model. Answer: B is incorrect. The stateful inspection firewall assures the connection between the two parties is valid and inspects packets from this connection to assure the packets are not malicious.