What command is used to test the reachability of a host on a network?

The command used to test the reachability of a host on a network is ping. This command operates by sending Internet Control Message Protocol (ICMP) Echo Request messages to the target host and waiting for Echo Reply messages in return. It essentially checks whether the destination is reachable across the network and provides feedback on the round-trip time for messages sent to the host.

By using ping, network administrators can quickly determine if a specific IP address or hostname is reachable, which is useful for troubleshooting network connectivity issues. The results can reveal information about possible delays, packet losses, or whether the host is down altogether.

In contrast, the other commands serve different purposes; traceroute is used to determine the path packets take to reach a destination, netstat displays network connections and statistics, and ipconfig provides information about the network configuration of the local machine. Each of these commands plays a unique role in network management and diagnostics, but none serve the direct purpose of testing reachability like ping.