A device that can look at all protocol headers up to the transport layer is called layer-4 firewall. Which one of the following statement is true layer-4 firewall?
(A) It cannot block all ICMP traffic
(B) It cannot block entire HTTP traffic during 9:00pm and 5:00am
(C) It cannot block TCP traffic from a specific user on a multi-user system during 9:00pm and 5:00am
(D) It cannot stop incoming traffic from a specific IP address but allow outgoing traffic to the same address