Service Name and Transport Protocol Port Number Registry

Last Updated

• 2026-11-04

Expert(s)

• TCP/UDP: Joe Touch; Eliot Lear, Kumiko Ono, Wes Eddy, Brian Trammell, and Michael Scharf
• SCTP: Michael Tuexen
• DCCP: Eddie Kohler and Yoshifumi Nishida

Reference

• RFC 6335: Internet Assigned Numbers Authority (IANA) Procedures for the Management of the Service Name and Transport Protocol Port Number Registry

Note

Service names and port numbers are used to distinguish between different services that run over transport protocols such as TCP, UDP, DCCP, and SCTP.

Service names are assigned on a First Come First Served basis, as described in RFC 6335.

Port numbers are divided into three ranges, with their uses and assignment procedures specified in Section 8.1.2 of RFC 6335:

• System Ports (0-1023) are assigned using the IETF Review or IESG Approval procedures.
• User Ports (1024-49151) are assigned using the IETF Review, IESG Approval, or Expert Review procedures.
• Dynamic and/or Private Ports (49152-65535) are not assigned.

The registration procedures for service names and port numbers are specified in RFC 6335, while the registration policies referenced above are defined in RFC 8126.

Assigned ports both System and User ports SHOULD NOT be used without or prior to IANA registration.

Registration Forms

• To request a new assignment, please use the Application for Service Names and User Port Numbers form.
• To modify an existing assignment, please use the Modify a Port Number Assignment form.

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