Service Name and Transport Protocol Port Number Registry

Last Updated
2026-08-17
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
[RFC6335]
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 process, as
documented in [RFC6335].

Port numbers are assigned in various ways, based on three ranges: System
Ports (0-1023), User Ports (1024-49151), and the Dynamic and/or Private
Ports (49152-65535); the different uses of these ranges are described in
[RFC6335]. According to Section 8.1.2 of [RFC6335], System Ports are 
assigned by the "IETF Review" or "IESG Approval" procedures described in 
[RFC8126]. User Ports are assigned by IANA using the "IETF Review" process, 
the "IESG Approval" process, or the "Expert Review" process, as per 
[RFC6335]. Dynamic Ports are not assigned.

The registration procedures for service names and port numbers are
described in [RFC6335].

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

************************************************************************
* PLEASE NOTE THE FOLLOWING:                                           *
*                                                                      *
* ASSIGNMENT OF A PORT NUMBER DOES NOT IN ANY WAY IMPLY AN             *
* ENDORSEMENT OF AN APPLICATION OR PRODUCT, AND THE FACT THAT NETWORK  *
* TRAFFIC IS FLOWING TO OR FROM A REGISTERED PORT DOES NOT MEAN THAT   *
* IT IS "GOOD" TRAFFIC, NOR THAT IT NECESSARILY CORRESPONDS TO THE     *
* ASSIGNED SERVICE. FIREWALL AND SYSTEM ADMINISTRATORS SHOULD          *
* CHOOSE HOW TO CONFIGURE THEIR SYSTEMS BASED ON THEIR KNOWLEDGE OF    *
* THE TRAFFIC IN QUESTION, NOT WHETHER THERE IS A PORT NUMBER          *
* REGISTERED OR NOT.                                                   *
************************************************************************

Request an Assignment
  [https://www.iana.org/protocols/apply]

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Service Name Port Number Transport Protocol Description Assignee Contact Registration Date Modification Date Reference Service Code Unauthorized Use Reported Assignment Notes
ripng 521 tcp ripng [Robert_E_Minnear] [Robert_E_Minnear]
ripng 521 udp ripng [Robert_E_Minnear] [Robert_E_Minnear]
ncube-lm 1521 tcp nCube License Manager [Maxine_Yuen] [Maxine_Yuen] 2022-02-14 Unauthorized Use Known on port 1521
ncube-lm 1521 udp nCube License Manager [Maxine_Yuen] [Maxine_Yuen] 2022-02-14 Unauthorized Use Known on port 1521
adaptecmgr 2521 tcp Adaptec Manager [Mark_Parenti] [Mark_Parenti]
adaptecmgr 2521 udp Adaptec Manager [Mark_Parenti] [Mark_Parenti]
mc3ss 3521 tcp Telequip Labs MC3SS [Michael_Sparks] [Michael_Sparks] 2002-06
mc3ss 3521 udp Telequip Labs MC3SS [Michael_Sparks] [Michael_Sparks] 2002-06
5210-5214 Unassigned
noteza 5215 tcp NOTEZA Data Safety Service [CNS_a.s.] [Pavel_Mendl_2] 2014-06-12
5215 udp Reserved
noteza 5215 sctp NOTEZA Data Safety Service [CNS_a.s.] [Pavel_Mendl_2] 2014-06-12
5216-5220 Unassigned
9501-9521 Unassigned

Contact Information

ID Name Organization Contact URI Last Updated
[CNS_a.s.] CNS a.s. (IT company registered in Czech republic) mailto:HAJN.L&cns.cz 2014-06-12
[Mark_Parenti] Mark Parenti mailto:map&ntc.adaptec.com
[Maxine_Yuen] Maxine Yuen mailto:maxine&hq.ncube.com
[Michael_Sparks] Michael Sparks mailto:msparks&telequiplabs.com 2002-06
[Pavel_Mendl_2] Pavel Mendl CNS a.s. (IT company registered in Czech republic) mailto:Pavel.MENDL&cns.cz 2014-06-12
[Robert_E_Minnear] Robert E. Minnear mailto:minnear&ipsilon.com