Port Number Reference

Look up what service uses a port — and which ports should never face the internet.

What you provide

Result

Port 443 — HTTPS

Encrypted web traffic. The default for essentially every modern site. Remember that a port’s registered service is a convention — it does not prove what is actually listening there.

Diagnostic telemetry
Port
443
Service
HTTPS
Protocol
TCP

What this cannot tell you

  • A reference of common assignments, not a scan. Knowing a port’s registered service does not tell you what is actually listening on it — any service can use any port.
  • Port assignments drift and many are used unofficially. Treat this as a convention guide, not proof.
  • It does not check your ports. It cannot see your machine or network — it only explains what a port number conventionally means.

Take this with you

Port Number Reference on RunTheTests — free browser-based netmath tools, no sign-up.