Implementing Cisco IP Routing (CCNP ROUTE, legacy) — Question 359

Which two statements about ICMP unreachable messages are true? (Choose two.)

Answer options

• A. They are sent when a route to the destination is missing from the routing table
• B. They can be enable and disable on a device only on a global level
• C. They are sent when a destination address responds to an ARP request
• D. They include the entire packet so that the source can identify the process that generated the message
• E. They include a portion of the original data so that the source can identify the process that generated the message

Correct answer: A, E

Explanation

Option A is correct because ICMP unreachable messages are indeed sent when there is no route to the destination in the routing table. Option E is also correct as these messages include a portion of the original data to assist the source in identifying the generating process. Options B, C, and D are incorrect; ICMP settings can be specific to interfaces, they are not related to ARP responses, and they do not include the entire packet.