Browse 200+ TCP, UDP, SCTP, and DCCP ports with IANA assignment status, the OS or platform that uses each one and why, real-world descriptions, and firewall notes. Filter by range (well-known, registered, dynamic), transport protocol, or platform, search by port or service, and page through results without slowing the browser.
Try a different keyword such as a port number (e.g. 3389),
a service name (https, postgres), or a protocol fragment.
What each protocol badge means.
| Cell | Meaning |
|---|---|
| Yes | Assigned by IANA and standardized, specified, or widely used on the port. |
| Unofficial | Not assigned by IANA, but standardized, specified, or widely used on the port. |
| Assigned | Assigned by IANA, but not standardized, specified, or widely used on the port. |
| No | Not assigned, standardized, specified, or widely used on the port. |
| Reserved | Reserved by IANA, generally to prevent collisions after a previous assignment was withdrawn. |
| — | Not applicable for that transport protocol. |
Three IANA ranges.
Well-known (0–1023). System ports for core services. On Unix-like systems, binding these requires superuser privileges.
Registered (1024–49151). Assigned by IANA on request. Usable without elevated privileges on most systems.
Dynamic / private (49152–65535). Cannot be registered; used for ephemeral allocation and custom services.
Practical reminders before you open anything.
A listed default is not a guarantee. Most services let you change the port. Verify the actual configuration, not the convention, before writing a rule.
TCP and UDP are separate rules. Many protocols (DNS, Kerberos, SIP, NTP) use both. Opening one transport does not open the other.
Mind the direction and the ephemeral range. Return traffic for outbound connections lands on dynamic ports (49152–65535); stateful firewalls handle this, packet filters may not.
Least privilege. Open the narrowest source/destination/port set that works. "Any/any" on a well-known port is a finding, not a rule.
Reference compiled from the IANA Service Name and Transport Protocol Port Number Registry and widely documented real-world usage. Assignments change — confirm against the current IANA registry for authoritative data.