Look up common TCP and UDP ports and their usual services

Network technicians consult it to find the service commonly associated with a TCP or UDP port during setup or troubleshooting.

Look up common TCP and UDP ports and their usual services. Everything runs in your browser, so no input is uploaded or stored.

How to use

Type the port number you want to check, for instance one you spotted in a log or a configuration file.
Run the lookup to see the service usually associated with that number.
Compare the answer with the transport actually used in your situation, TCP or UDP, before drawing conclusions.
Clear the field whenever you want to check another number right away.

Example

The sample uses port 53. After the lookup, read the service name and ask yourself whether it fits the traffic you are investigating, because a diverted use or a service moved to a non standard port will not appear here. The answer only describes the usual convention.

Input

Limits and formats

The reference covers the best known ports, so an unusual number may return nothing at all.
What you see is the customary purpose of a port, not proof of what is running on a specific machine.
Software can be configured to listen on a different port from the conventional one.
Treat this page as a troubleshooting aid rather than an official standard document.

Where processing happens

The lookup relies on a list built into the page and runs inside your browser. The number you type goes nowhere and does not survive your visit; it is used only to find the matching entry.

Frequently asked questions

Does TCP or UDP change what I get?

The page covers the main ports for both transports. Before reading too much into the answer, check which transport is used in the traffic you are studying, since that detail can change how you interpret the service shown.

Can it tell me whether a port is open on my machine?

No. It only explains the customary use of a port number. It does not scan your device and cannot say whether a port is open, closed or blocked by a firewall.

Why do some numbers return no result?

The reference is limited to the best known ports. A number assigned to a specific application or reserved for internal use may not be listed, even if it is genuinely in use on your network.