The Internet Control Message Protocol (ICMP) is used for error reporting and diagnostics in IP
networks.
Control Messages: ICMP messages inform the sender about network issues, such as:
Destination Unreachable: Indicates that the packet could not reach the intended destination.
Echo Request/Reply: Used in ping to test connectivity.
Time Exceeded: Indicates that a packet's TTL (Time to Live) has expired.
Common Usage: Troubleshooting network issues (e.g., ping and traceroute).
Other options analysis:
A . TLS protocol version unsupported: Related to SSL/TLS, not ICMP.
C . 404 not found: An HTTP status code, unrelated to ICMP.
D . Webserver is available: A general statement, not an ICMP message.
CCOA Official Review Manual, 1st Edition Reference:
Chapter 4: Network Protocols and ICMP: Discusses ICMP control messages.
Chapter 7: Network Troubleshooting Techniques: Explains ICMP’s role in diagnostics.
