Port Number Lookup

What this tool does

Port Number Lookup is a searchable reference table of well-known and commonly used TCP/UDP port numbers, from classic services like SSH (22) and HTTPS (443) to common database and development server ports, each with its protocol and a brief description.

Remembering which port a given service conventionally uses, or figuring out what’s likely running on an unfamiliar open port, is a routine need in networking and development work that a quick reference table handles faster than searching each time.

This table covers the most commonly encountered ports, classic internet services (HTTP, HTTPS, SSH, FTP, DNS), mail protocols, databases (MySQL, PostgreSQL, MongoDB, Redis), and common development server defaults, each with its protocol (TCP/UDP) and a brief description, searchable by number or name.

How to use Port Number Lookup

1. Search by port number (e.g. 443) or service name (e.g. "database").
2. Review the matching results and their descriptions.
3. Note the protocol (TCP/UDP) for firewall or config rules.
4. Cross-check an unfamiliar open port against the table before assuming what it runs.

Tips for better results

• Ports 0-1023 are "well-known" ports, historically requiring administrator/root privileges to bind on Unix-like systems, which is why many classic internet services (HTTP, SSH, DNS) use low numbers.
• Nothing technically stops a service from running on a non-standard port; these are just conventions, a web server could just as easily listen on port 9999 as port 80.
• Several common development server defaults are included (3000, 5000, 8080) since they come up constantly when debugging local environments, even though they aren’t officially "well-known" in the strict sense.
• Both TCP and UDP ports share the same numbering space but are entirely separate; a service can use TCP port 53 and a completely different service could independently use UDP port 53.

Common use cases

• Quickly recalling which port a service conventionally uses when writing firewall rules or documentation.
• Identifying what might be running on an unfamiliar open port found during a network scan.
• Looking up common development server default ports when setting up a local environment.
• Learning the well-known/registered/dynamic port range categories.

Common mistakes to avoid

• Assuming a port number always means a specific service is running there; these are conventions, not guarantees, always verify what’s actually listening rather than inferring purely from the port number.
• Confusing TCP and UDP for the same port number as necessarily being the same service; they’re independent, a given number can be used completely differently by each protocol.
• Forgetting that binding to ports below 1024 traditionally requires elevated privileges on Unix-like systems, a common gotcha when a service unexpectedly fails to start on a "well-known" port.