Port Lookup

How to use it

1. Type a port number (for example 443) or part of a service name (for example sql) in the search box.
2. The table filters as you type — matching by number prefix or service-name substring.
3. Leave the box empty to list the entire built-in table of about 60 well-known ports.
4. Each row shows the port, service name, TCP/UDP protocol and a one-line purpose.
5. A counter below the input shows how many of the built-in entries match.

Common use cases

• Reading firewall or cloud security-group rules — checking what 445, 3389 or 6443 actually expose before allowing them.
• Debugging a connection refused error — confirming which service normally listens on the port you tried.
• Reviewing a server checklist — looking up unfamiliar ports such as 11211 or 27017 found in a port scan.
• Choosing a port for a new service — avoiding well-known ports already used by databases, message brokers or dev servers.

Why it stays private

The port table is built into the page and filtering happens entirely in your browser. There are no lookups, no requests and no history of what you searched.

FAQ

Q: How complete is the port list? A: It is a curated table of about 60 widely seen ports, not the full IANA registry. It covers the ones that show up most often in everyday work: SSH, HTTP/HTTPS, databases, message brokers, remote desktop, containers and common proxies.

Q: Why do some ports list both TCP and UDP? A: Some protocols genuinely use both transports. DNS, for example, mostly uses UDP but switches to TCP for large responses or zone transfers, so the entry is marked TCP/UDP.

Q: Does this tool query any online port database? A: No. All data is embedded in the page and filtering runs locally, so it also works with the network disconnected.