Implementing Cisco IP Routing (CCNP ROUTE, legacy) — Question 264

Which condition must be met before a router can send an ICMP redirect message?

Answer options

• A. The IP address of the sending device must be in the same subnet as the next hop.
• B. The ingress and egress interfaces on the device must be different.
• C. The datagram must be source-routed.
• D. ICMP echo requests must have been disabled globally.

Correct answer: A

Explanation

For a router to send an ICMP redirect message, the sending device's IP address must be in the same subnet as the next hop, which allows the router to inform the sender of a more efficient routing path. Options B, C, and D do not correctly describe conditions for an ICMP redirect message; B relates to interface usage, C involves source routing which is not required, and D concerns echo requests rather than redirects.