Which Internet Control Message Protocol (ICMP) message is sent by a host in the network to test connectivity
with another host?

A.
ICMP redirect message

B.
ICMP echo-request message

C.
ICMP time-exceeded message

D.
ICMP destination-unreachable message

Explanation:
An ICMP echo-request message is sent by a host in the network to test connectivity with another host. An ICMP
echo-request message is generated by the ping command. ICMP is a network-layer protocol that uses packets
for reporting informational messages. When a host receives an echo-request (a ping), it responds by sending
back an echo-reply message.
An ICMP redirect message is sent to the source host by the router to make the routing process more efficient.
An ICMP time-exceeded message indicates that the Time-to-Live (TTL) field of the IP packet has reached zero.
An ICMP destination-unreachable message is sent by the router to indicate that the router is unable to send the
packet to its intended destination.
Objective:
Network Fundamentals
Sub-Objective:
Configure, verify, and troubleshoot IPv4 addressing and subnetting

Cisco > Internetworking Technology Handbook > Internet Protocols (IP)