Question

A layer-4 firewall (a device that can look at all protocol headers up to the transport layer) CANNOT 

(A) block entire HTTP traffic during 9:00PM and 5:00AM 

(B) block all ICMP traffic 

(C) stop incoming traffic from a specific IP address but allow outgoing traffic to the same IP address 

(D) block TCP traffic from a specific user on a multi-user system during 9:00PM and 5:00AM

Answer 1

(A) block entire HTTP traffic during 9:00PM and 5:00AM

Since it is a layer 4 firewall it cannot block application layer protocol like HTTP