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
pirp 553 tcp pirp [D_J_Bernstein] [D_J_Bernstein]
pirp 553 udp pirp [D_J_Bernstein] [D_J_Bernstein]
sna-cs 1553 tcp sna-cs [Tony_Sowter] [Tony_Sowter]
sna-cs 1553 udp sna-cs [Tony_Sowter] [Tony_Sowter]
efidiningport 2553 tcp efidiningport [Lynn_Carter] [Lynn_Carter]
efidiningport 2553 udp efidiningport [Lynn_Carter] [Lynn_Carter]
rbr-discovery 3553 tcp Red Box Recorder ADP [Simon_Jolly] [Simon_Jolly] 2002-07
rbr-discovery 3553 udp Red Box Recorder ADP [Simon_Jolly] [Simon_Jolly] 2002-07
icshostsvc 4553 tcp ICS host services [Gordan_Vosicki] [Gordan_Vosicki] 2009-09-23
4553 udp Reserved
5508-5539 Unassigned
sgi-eventmond 5553 tcp SGI Eventmond Port [Andrei_Vilkotski] [Andrei_Vilkotski] 2003-06
sgi-eventmond 5553 udp SGI Eventmond Port [Andrei_Vilkotski] [Andrei_Vilkotski] 2003-06
8504-8553 Unassigned
rdm-tfs 21553 tcp Raima RDM TFS [Paul_Johnson] [Paul_Johnson] 2011-05-02
21553 udp Reserved
24466-24553 Unassigned
rbr-debug 44553 tcp REALbasic Remote Debug [Aaron_Ballman] [Aaron_Ballman] 2004-11
rbr-debug 44553 udp REALbasic Remote Debug [Aaron_Ballman] [Aaron_Ballman] 2004-11

Contact Information

ID Name Contact URI Last Updated
[Aaron_Ballman] Aaron Ballman mailto:aaron&realsoftware.com 2004-11
[Andrei_Vilkotski] Andrei Vilkotski mailto:andreiv&sgi.com 2003-06
[D_J_Bernstein] D. J. Bernstein mailto:ports&box.cr.yp.to 2018-04-05
[Gordan_Vosicki] Gordan Vosicki mailto:admin&icsa.ch 2009-09-23
[Lynn_Carter] Lynn Carter mailto:carterl&execpc.com
[Paul_Johnson] Paul Johnson mailto:paul.johnson&raima.com 2011-05-02
[Simon_Jolly] Simon Jolly mailto:simon.jolly&origin-data.co.uk 2002-07
[Tony_Sowter] Tony Sowter mailto:ts&datcon.co.uk