In networking, what does a 'ping' command primarily test?

The 'ping' command primarily tests connectivity to a host. It works by sending Internet Control Message Protocol (ICMP) echo request packets to the specified address and listening for echo replies. When a device receives a ping, it responds back with an echo reply, indicating that it is reachable over the network. This capability to check if a specific IP address or hostname is reachable helps network administrators diagnose connection issues and assess network availability.

The command provides a simple yet effective way to determine whether a device is online and responsive. Thus, if you successfully receive replies, it confirms that there is a functional path between your device and the target device, indicating that the connection is working properly.