What command is commonly used to test connectivity between two hosts?

The command commonly used to test connectivity between two hosts is "Ping." This utility sends Internet Control Message Protocol (ICMP) echo request packets to the target host and waits for an echo reply. By monitoring the replies, it provides information on the round-trip time and can illustrate if the host is reachable across the network.

Ping is particularly useful for diagnosing network issues, as it helps to determine if a device is online and how quickly it responds to requests. If there are no replies, it may indicate a network problem, such as a downed link or an unresponsive device.

Traceroute is focused on identifying the path taken by packets across the network, which helps in analyzing the route rather than testing direct connectivity. Netstat provides information about active connections and protocol statistics but does not test connectivity directly. ARP is used for resolving network layer addresses into link layer addresses, playing a role in local network communication, but it does not serve the purpose of testing connectivity between disparate hosts.