Which protocol is normally used to communicate errors or other conditions at the IP layer, but has also been used to conduct denial-of-service attacks?

A.
TCP

B.
ICMP

C.
SNMP

D.
UDP

Explanation:
ICMP is used for the PING command. It can be used in a smurf, teardrop, buffer overflow, and the ping of death attacks.
Incorrect Answers:
A: TCP does not run at the IP layer (Layer 3), TCP runs t the transport layer (Layer 4)
B: SNMP does not run at layer 3 IP Layer). SNMP runs at the application layer (Layer 7)
D: UDP does not run at the IP layer (Layer 3), UDP runs at the transport layer (Layer 4)