Ping (thought to stand for Packet Internet Groper) is probably the most widely available utility on TCP/IP systems, allowing users to learn the status of other systems, as well as the expected round-trip delay between the local and remote host. Ping is useful for a number of pragmatic reasons. Prior to attempting to establish a TCP virtual circuit, a local host might ping the intended destination to determine that the destination host is, in fact, up and reachable.
The Ping utility confirms that physical connectivity, data link parameters, and IP addresses and masks are functioning properly on all devices interconnecting the pinging and pinged devices. Ping uses Internet Control Message Protocol (ICMP) Echo and Echo Reply messages. Ping implementations are included in UNIX, all version of Windows since Windows 95, Macs, and most routers.
Ping has the following general command-line format (where items in square brackets  are optional):
ping [-s] host_name [size] [quantity]
In the first test on the accompanying visual, the host thumper.bellcore.com is pinged to determine whether it is up and running. This simple use of the command contains no optional parameters.
In the second test, the -s parameter is used to tell the local system to send an ICMP Echo message every second. The optional size and quantity parameters are not specified, so default values are used; 64 byte messages will be sent continuously until the program is interrupted. The results of the second test list the round-trip delay experienced by each Echo message returned to the sending host.
|<mp3>http://podcast.hill-vt.com/podsnacks/2007q3/ping.mp3%7Cdownload</mp3> | Ping|