Which of the following devices should you use to keep machines behind it anonymous? (Select the best answer.)

A. Caching proxy
B. IP proxy
C. Circuit-level gateway
D. Firewall
E. UTM

B. IP proxy secures a network by keeping the computers behind it anonymous. Caching proxies store HTTP or other information so that clients don't have to actually contact a remote server. Circuit-level gateways apply security mechanisms when connections are established; they are a type of filtering. Firewalls protects the LAN, and although some firewall devices include an IP proxy, they won't necessarily do so. Although a UTM (unified threat management) device might include an IP proxy, it won't necessarily have one, so the answer "IP proxy" specifically is the better answer.