Which ICMP message could be used with traceroute to map network topology?
The ICMP message that is commonly used with traceroute to map network topology is the "Time Exceeded" message.
When traceroute is executed, it sends out a series of ICMP packets with an incrementing TTL (Time-to-Live) value. The TTL field specifies how many router hops the packet can traverse before being discarded. Each router that the packet passes through decrements the TTL value by one, and when the TTL reaches zero, the router discards the packet and sends an ICMP Time Exceeded message back to the source. This message contains information about the router that sent it, including its IP address, and allows traceroute to identify the network topology between the source and destination.
The Echo Request and Echo Reply messages are used for ICMP ping operations, where a host sends a packet to another host and waits for an echo reply. The Redirect message is used by routers to inform a host that a better next-hop router exists for a particular destination. The Router Selection and Address Mask Request messages are not commonly used in network troubleshooting or mapping.