ping

Ping is a computer network administration utility used to test reachability of a host on an IP network and to measure the round-trip time for messages sent from the originating host to the destination. It operates by sending a short message, typically called an ICMP Echo Request, and waiting for a corresponding Echo Reply. The name is derived from sonar pings and is sometimes explained as a play on “Packet Internet Groper.”

Ping was created by Mike Muuss in 1983 while developing network tools at the U.S. Army Research Laboratory. The program quickly became a standard diagnostic tool and is included in most operating systems and network devices. The basic concept has remained stable, though implementations have expanded to support IPv4 and IPv6 and various command-line options.

Each Echo Request contains a payload and an identifier and sequence number so responses can be matched to requests. When a destination replies, the software records the time elapsed, called the round-trip time (RTT). Ping can report statistics such as the minimum, maximum, average RTT, and packet loss over a series of probes. The exact behavior and default packet sizes vary by platform.

Ping is a useful initial diagnostic tool but does not guarantee full connectivity or diagnose higher-layer problems. ICMP traffic can be blocked or deprioritized by firewalls and routers, which can make ping appear unsuccessful even when other services are reachable. It can be used for latency testing, basic uptime checks, or to detect intermittent connectivity. Some networks use rate limiting to block ICMP flood.

Variants include ping for IPv4 and ping6 for IPv6 on some systems; implementations may have different command syntax. Related tools include traceroute, which discovers the path to a host by sending probes with varying TTL values, and more advanced network performance measurement tools.