Which of the following is an effective method for controlling downloading of files via FTP?
A. An application-layer gateway, or proxy firewall, but not stateful inspection firewalls
B. An application-layer gateway, or proxy firewall
C. A circuit-level gateway
D. A first-generation packet-filtering firewall
Explanation:
Application-layer gateways, or proxy firewalls, are an effective method for controlling downloading of files via FTP. Because FTP is an OSI application-layer protocol, the most effective firewall needs to be capable of inspecting through the application layer.