Port number lookup
A quick reference for the common ports you open in a firewall or see in a network scan.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter port number.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
The number is matched against a list of common IANA-registered or de facto ports. Range per RFC 6335: 0 to 1023 system ports, 1024 to 49151 registered user ports, 49152 to 65535 dynamic ports.
Example
Inputs: Port number = 443. Result: Service: HTTPS; Port range: System (well-known) port; Transport: TCP/UDP.
Limits and caveats
- The list covers the most common ports, not the full IANA registry.
- Any program can listen on any port, so the number alone does not prove which service is running.
Questions about this tool
What is the difference between ports 587 and 465 for mail?
587 is submission with STARTTLS upgrade; 465 is submission over TLS from the first byte.
Does HTTPS use UDP?
Yes. HTTP/3 runs over QUIC on UDP 443, alongside TCP 443 for older versions.
What are dynamic ports?
Ports 49152 to 65535, which the OS picks temporarily for the client side of connections.