About Well-Known Ports

40+ standard TCP/UDP ports — search by number, service, or keyword. Part of the DevTools Surf developer suite. Browse more tools in the Networking collection.

Use Cases

• Identify what service a port number belongs to
• Find the default port before configuring a firewall
• Troubleshoot connection errors by cross-referencing port usage
• Document internal-service port allocations for onboarding docs

Tips

• Range 0-1023 is 'well-known' per IANA; requires root to bind on Unix
• Search by port number, service name, or any keyword in the notes
• Many common dev ports are listed (3000, 5173, 11434)

Fun Facts

• Port 22 (SSH) was registered by Tatu Ylönen in 1995 — he emailed IANA saying 'we'd like port 22' and they just... gave it to him.
• Port 80 (HTTP) was assigned by Tim Berners-Lee in 1991. Before that, the World Wide Web used port 2784 during its CERN development phase.
• Ports 49152–65535 are 'ephemeral' ports — your OS randomly picks one for each outgoing TCP connection, which is why 'netstat' shows so many high-numbered ports.

FAQ

How is this different from Port Reference Lookup?

Well-Known Ports focuses on the 0-1023 range — the 'system' ports that typically require root to bind. Port Reference Lookup covers the full spectrum.

Are these ports reserved?

IANA reserved, yes. Real systems can still use them for other services, but it's bad practice and confuses users.

What's 80 vs 8080?

80 is the registered HTTP port. 8080 is an unofficial convention for HTTP alternate (often dev servers). Same protocol, different port.

Are TCP and UDP ports separate?

Yes — each protocol has its own port number space. A service can use both (DNS uses TCP and UDP 53). The tool shows both columns.