Glossary · Networking

Ping

Ping is a diagnostic tool that sends ICMP echo requests to a host and reports whether it replies and how long the round trip takes.

Updated October 6, 2026

Ping is a command-line utility that sends ICMP echo requests to a target and measures the round-trip time of each reply. It reports reachability, latency and packet loss in one short test.

Why it matters

Ping is the first step in network troubleshooting: it tells you whether a host is reachable at the IP level and roughly how far away it is. Consistent high times point to distance or congestion, varying times show jitter, and missing replies show loss. It tests only the network path, not whether a web service is working.

Example

$ ping -c 4 example.com
64 bytes: icmp_seq=1 ttl=56 time=18.2 ms
64 bytes: icmp_seq=2 ttl=56 time=18.9 ms
64 bytes: icmp_seq=3 time=Request timeout
4 packets transmitted, 3 received, 25% packet loss

One of four requests went unanswered, so the loss is 25 percent.

Common mistakes

  • Treating a failed ping as proof the website is down. The host may block ICMP while serving HTTPS normally.
  • Treating a successful ping as proof the site works. A server can answer ICMP while the web app is broken.
  • Judging quality from a single reply instead of a run of several.

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