ping (Packet Internet Groper)
A program that system administrators and hackers or crackers use to determine whether a specific computer is currently online and accessible. Pinging works by sending a packet to the specified IP address and waiting for a reply; if a reply is received, the computer is deemed to be online and accessible.
A utility that is used to verify that a data packet is capable of being distributed to an address without errors. The ping utility is commonly used to check for network errors.