Home » CompTIA » JK0-019 » Which of the following protocols needs to be denied?
A network technician is concerned that an attacker is attempting to penetrate the network, and wants to set a rule on the firewall to prevent the attacker from learning which IP addresses are valid on the network. Which of the following protocols needs to be denied?
A. TCP
B. SMTP
C. ICMP
D. ARP
Correct Answer: C
Explanation/Reference:
Explanation: The Internet Control Message Protocol (ICMP) is one of the core protocols of the Internet Protocol Suite. It is used by network devices, like routers, to send error messages indicating, for example, that a requested service is not available or that a host or router could not be reached. ICMP can also be used to relay query messages. It is assigned protocol number 1.
