Ping is an old Unix utility which is pretty useful even today. The basic idea behind Ping is to find out whether the network is reachable and alive or not. Ping basically sends an ICMP echo request and then waits for an ICMP echo response the roundtrip time is calculated from the time at which the request was sent and the time at which a response is received. For more information on ICMP, please see RFC 792. -Ping is an old Unix utility which is pretty useful even today. The basic idea behind Ping is to find out whether the network is reachable and alive or not. Ping basically sends an ICMP echo request and then waits for an ICMP echo response　the roundtrip time is calculated from the time at which the request was sent and the time at which a response is received. For more information on ICMP, please see RFC 792.