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
conference 531 tcp chat
conference 531 udp chat
rap-listen 1531 tcp rap-listen [Phil_Servita] [Phil_Servita]
rap-listen 1531 udp rap-listen [Phil_Servita] [Phil_Servita]
ito-e-gui 2531 tcp ITO-E GUI [Michael_Haeuptle] [Michael_Haeuptle]
ito-e-gui 2531 udp ITO-E GUI [Michael_Haeuptle] [Michael_Haeuptle]
joltid 3531 tcp Joltid [Ahti_Heinla] [Ahti_Heinla] 2002-06
joltid 3531 udp Joltid [Ahti_Heinla] [Ahti_Heinla] 2002-06
outlaws 5310 tcp Outlaws [Richard_Fife] [Richard_Fife]
outlaws 5310 udp Outlaws [Richard_Fife] [Richard_Fife]
5311 Unassigned 2004-05-07
permabit-cs 5312 tcp Permabit Client-Server [Jered_Floyd] [Jered_Floyd] 2004-06
permabit-cs 5312 udp Permabit Client-Server [Jered_Floyd] [Jered_Floyd] 2004-06
rrdp 5313 tcp Real-time & Reliable Data [Ted_Hoshi] [Ted_Hoshi] 2004-06
rrdp 5313 udp Real-time & Reliable Data [Ted_Hoshi] [Ted_Hoshi] 2004-06
opalis-rbt-ipc 5314 tcp opalis-rbt-ipc [Laurent_Domenech] [Laurent_Domenech]
opalis-rbt-ipc 5314 udp opalis-rbt-ipc [Laurent_Domenech] [Laurent_Domenech]
hacl-poll 5315 tcp HA Cluster UDP Polling [Hoa_Nguyen] [Hoa_Nguyen]
hacl-poll 5315 udp HA Cluster UDP Polling [Hoa_Nguyen] [Hoa_Nguyen]
hpbladems 5316 tcp HPBladeSystem Monitor Service [Alan_Minchew] [Alan_Minchew] 2011-05-23 2011-05-16
5316 udp Unassigned 2011-05-16
hpdevms 5317 tcp HP Device Monitor Service [Alan_Minchew] [Alan_Minchew] 2011-05-16
5317 udp Reserved
pkix-cmc 5318 tcp PKIX Certificate Management using CMS (CMC) [IESG] [IETF_Chair] 2026-02-13 [RFC10003]
5318 udp Reserved
roughtime 5319 tcp Roughtime time synchronization [IESG] [IETF_Chair] 2026-03-27 [RFC-ietf-ntp-roughtime-19]
roughtime 5319 udp Roughtime time synchronization [IESG] [IETF_Chair] 2026-03-27 [RFC-ietf-ntp-roughtime-19]

Contact Information

ID Name Organization Contact URI Last Updated
[Ahti_Heinla] Ahti Heinla mailto:ahti&ahti.bluemoon.ee 2002-06
[Alan_Minchew] Alan Minchew mailto:alan.minchew&hp.com 2011-05-23
[Hoa_Nguyen] Hoa Nguyen mailto:hoan&cup.hp.com
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Jered_Floyd] Jered Floyd mailto:jered&permabit.com 2004-06
[Laurent_Domenech] Laurent Domenech Opalis mailto:ldomenech&opalis.com
[Michael_Haeuptle] Michael Haeuptle mailto:Michael_Haeuptle&hp.com
[Phil_Servita] Phil Servita mailto:meister&ftp.com
[Richard_Fife] Richard Fife mailto:richardf&lucasarts.com
[Ted_Hoshi] Ted Hoshi mailto:tetsuo.hoshi&jp.yokogawa.com 2004-06