Which protocol is used for both ping and traceroute?

The correct answer is based on the functionality and purpose of the Internet Control Message Protocol (ICMP). ICMP is primarily used for diagnostic tools in network environments, such as the tools mentioned: ping and traceroute.

When you use the ping command, it sends ICMP Echo Request messages to a specified host and awaits ICMP Echo Reply messages. This is how it determines the reachability of the host and measures the round-trip time for messages sent to the destination.

Similarly, traceroute utilizes ICMP to map the path data takes from one network to another. It does this by sending packets with incrementally increasing Time to Live (TTL) values, which prompts intermediate routers along the path to respond with Time Exceeded messages. These responses are also ICMP messages, which help identify the route taken by the packets.

The other protocols listed serve different purposes. TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are primarily used for data transmission at the transport layer, focusing on how data is being sent rather than network diagnostics. ARP (Address Resolution Protocol) operates at the network layer and is used for mapping an IP address to a physical MAC address on a local area network, which does not relate to the diagnostic functions of ping and