Answer : Ping
Ping is a networking utility program or a tool to test if a particular host is reachable. It is a diagnostic that checks if your computer is connected to a server. Ping, a term taken from the echo location of a submarine, sends data packet to a server and if it receives a data packet back, then you have a connection. It uses a series of Internet Control Message Protocol (ICMP) Echo messages to determine: Whether a remote host is active or inactive. The round-trip delay in communicating with the host.
