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
TCP(Transmission Control Protocol)- part of TCP/IP suite operating at L4 of OSI. Connection-oriented
SMTP(Simple Mail Transfer Protocol)- main protocol to send e-mail in Internet
ICMP(Internet Control Message Protocol)- connectionless single packet that determine connectivity b/w 2 hosts
ARP(Address Resolution Protocol)- protocol in TCP/IP suite used with command-line utility of same name to determine MAC add. that corresponds to particular IP add.
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