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
nmsp 537 tcp Networked Media Streaming Protocol [Paul_Santinelli_Jr] [Paul_Santinelli_Jr]
nmsp 537 udp Networked Media Streaming Protocol [Paul_Santinelli_Jr] [Paul_Santinelli_Jr]
sdsc-lm 1537 tcp isi-lm [Len_Wanger] [Len_Wanger]
sdsc-lm 1537 udp isi-lm [Len_Wanger] [Len_Wanger]
upgrade 2537 tcp Upgrade Protocol [Breck_Auten] [Breck_Auten]
upgrade 2537 udp Upgrade Protocol [Breck_Auten] [Breck_Auten]
ni-visa-remote 3537 tcp Remote NI-VISA port [Sinnadurai_Dharshan] [Sinnadurai_Dharshan] 2002-07
ni-visa-remote 3537 udp Remote NI-VISA port [Sinnadurai_Dharshan] [Sinnadurai_Dharshan] 2002-07
wssauthsvc 4537 tcp WSS Security Service [Mark_Tirschwell] [Mark_Tirschwell] 2006-01
wssauthsvc 4537 udp WSS Security Service [Mark_Tirschwell] [Mark_Tirschwell] 2006-01
9537-9554 Unassigned
caldsoft-backup 22537 tcp CaldSoft Backup server file transfer [CaldSoft] [Mark_Caldwell] 2011-08-12
22537 udp Reserved

Contact Information

ID Name Contact URI Last Updated
[Breck_Auten] Breck Auten mailto:bauten&dst-inc.com
[CaldSoft] CaldSoft mailto:development&caldsoft.co.uk 2011-08-12
[Len_Wanger] Len Wanger mailto:lrw&sdsc.edu
[Mark_Caldwell] Mark Caldwell mailto:development&caldsoft.co.uk 2011-08-12
[Mark_Tirschwell] Mark Tirschwell mailto:mark.tirschwell&wallstreetsystems.com 2006-01
[Paul_Santinelli_Jr] Paul Santinelli Jr. mailto:psantinelli&narrative.com
[Sinnadurai_Dharshan] Sinnadurai Dharshan mailto:sinnadurai.dharshan&ni.com 2002-07