Which protocol is used for diagnostic commands such as Ping and Traceroute?

The correct answer is based on the role of the Internet Control Message Protocol (ICMP) in network communications. ICMP is specifically designed for sending error messages and operational information related to IP processing, making it essential for network diagnostics.

For example, the Ping command utilizes ICMP to check the reachability of a host on an IP network by sending Echo Request messages and waiting for Echo Reply messages. This helps determine if a device is reachable and measures the round-trip time for messages sent to the destination. Similarly, the Traceroute command relies on ICMP to map the route taken by packets across a network, helping in identifying the path and troubleshooting routing issues.

The other options relate to specific functionalities that do not directly align with diagnostic commands. SSH is primarily focused on secure shell access to devices, HTTPS provides a secure communication channel over the web, and SNMP is used for network management and monitoring but does not serve diagnostic functions like Ping and Traceroute do. Hence, ICMP stands out as the protocol dedicated to issuing diagnostic commands, making it the correct choice.