CompTIA Security+ SY0-701 Practice Question

An application-level gateway operates at the highest layer of the OSI model and can inspect the contents of network traffic to make filtering decisions based on the actual data being transmitted. This allows it to detect and block specific commands or payloads within protocols like Hypertext Transfer Protocol (HTTP) and File Transfer Protocol (FTP), which is necessary to prevent threats such as malware or exploits that are hidden within legitimate traffic. Other firewall types, such as packet-filtering firewalls and circuit-level gateways, do not inspect the data payload and cannot make decisions based on the content of the communication.