Ping is a basic internet program that allows a user to test and verify if a particular destination IP address exists and can accept requests. It is a command-line program designed to allow network administrators to track the availability status of different devices in a network. Ping measures the round-trip time for messages sent from the originating host to a destination computer that are echoed back to the source. It works by sending an Internet Control Message Protocol (ICMP) Echo Request to a specified interface on the network and waiting for a reply. When a ping command is issued, an echo request is sent to the target device or a specified IP address. The local computer that sent the request then waits for the response of the remote host. If available or online, the target computer sends an echo response packet back to the originating computer.

Ping is used diagnostically to ensure that a host computer the user is trying to reach is operating. It is most often used to determine whether a host computer can respond to access requests from other devices in a network. IT admins can schedule a continuous ping network test to monitor devices up/down status and receive timely alerts upon test failure, indicating the need for troubleshooting. In multiplayer online video games, ping refers to the network latency between a player's computer (client), and either the game server or another client (i.e. peer) . Ping represents "latency" between your PC and the server; i.e. how many milliseconds will pass between you clicking the mouse (or something), the server receiving the instruction, and your PC then receiving the result.

The name "ping" comes from active sonar terminology that sends a pulse of sound and listens for the echo to detect objects underwater. The backronym Packet InterNet Groper for PING has been used for over 30 years.