Service Name and Transport Protocol Port Number Registry

Last Updated
2026-06-17
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
webphone 21845 udp webphone [Toby_Hosterman] [Toby_Hosterman]
netspeak-is 21846 tcp NetSpeak Corp. Directory Services [Toby_Hosterman] [Toby_Hosterman]
netspeak-is 21846 udp NetSpeak Corp. Directory Services [Toby_Hosterman] [Toby_Hosterman]
netspeak-cs 21847 tcp NetSpeak Corp. Connection Services [Toby_Hosterman] [Toby_Hosterman]
netspeak-cs 21847 udp NetSpeak Corp. Connection Services [Toby_Hosterman] [Toby_Hosterman]
netspeak-acd 21848 tcp NetSpeak Corp. Automatic Call Distribution [Toby_Hosterman] [Toby_Hosterman]
netspeak-acd 21848 udp NetSpeak Corp. Automatic Call Distribution [Toby_Hosterman] [Toby_Hosterman]
netspeak-cps 21849 tcp NetSpeak Corp. Credit Processing System [Toby_Hosterman] [Toby_Hosterman]
netspeak-cps 21849 udp NetSpeak Corp. Credit Processing System [Toby_Hosterman] [Toby_Hosterman]
21850-21999 Unassigned
optocontrol 22001 tcp OptoControl [Kevin_Kuhns] [Kevin_Kuhns]
optocontrol 22001 udp OptoControl [Kevin_Kuhns] [Kevin_Kuhns]
22006-22124 Unassigned
dcap 22125 tcp dCache Access Protocol [Christoph_Anton_Mitt] [Christoph_Anton_Mitt] 2009-03-10
22125 udp Reserved
22126-22127 Unassigned
gsidcap 22128 tcp GSI dCache Access Protocol [Christoph_Anton_Mitt] [Christoph_Anton_Mitt] 2009-03-10
22128 udp Reserved
22129-22221 Unassigned
codemeter-cmwan 22351 tcp TPC/IP requests of copy protection software to a server [WIBU-SYSTEMS_AG] [Wolfgang_Völker_2] 2013-06-25
22351 udp Reserved
22801-22950 Unassigned
brf-gw 22951 tcp Telerate Information Platform WAN [Timo_Sivonen] [Timo_Sivonen]
brf-gw 22951 udp Telerate Information Platform WAN [Timo_Sivonen] [Timo_Sivonen]
inovaport1 23000 tcp Inova LightLink Server Type 1 [Chris_Koeritz_3] [Chris_Koeritz_3] 2006-10
inovaport1 23000 udp Inova LightLink Server Type 1 [Chris_Koeritz_3] [Chris_Koeritz_3] 2006-10
inovaport2 23001 tcp Inova LightLink Server Type 2 [Chris_Koeritz_3] [Chris_Koeritz_3] 2006-10
inovaport2 23001 udp Inova LightLink Server Type 2 [Chris_Koeritz_3] [Chris_Koeritz_3] 2006-10
23054-23271 Unassigned
s102 23272 udp S102 application [Kimmo_Kymalainen] [Kimmo_Kymalainen] 2009-08-26
novar-alarm 23401 tcp Novar Alarm [Keith_Kilroy] [Keith_Kilroy] 2006-02
novar-alarm 23401 udp Novar Alarm [Keith_Kilroy] [Keith_Kilroy] 2006-02
med-fsp-rx 24001 tcp med-fsp-rx [Juergen_Fischbach] [Juergen_Fischbach]
med-fsp-rx 24001 udp med-fsp-rx [Juergen_Fischbach] [Juergen_Fischbach]
24007-24241 Unassigned
ild 24321 tcp Isolv Local Directory [Mitchell_Bass] [Mitchell_Bass] 2005-08
ild 24321 udp Isolv Local Directory [Mitchell_Bass] [Mitchell_Bass] 2005-08
udpstp 24601 udp UDP-based IP-Layer Capacity and Performance Measurement protocol [IESG] [IETF_Chair] 2025-09-26 [RFC9946]
24601 tcp Reserved
24681-24726 Unassigned
24851-24921 Unassigned
icl-twobase1 25000 tcp icl-twobase1 [J_A_Sever] [J_A_Sever]
icl-twobase1 25000 udp icl-twobase1 [J_A_Sever] [J_A_Sever]
icl-twobase2 25001 tcp icl-twobase2 [J_A_Sever] [J_A_Sever]
icl-twobase2 25001 udp icl-twobase2 [J_A_Sever] [J_A_Sever]
icl-twobase10 25009 tcp icl-twobase10 [J_A_Sever] [J_A_Sever]
icl-twobase10 25009 udp icl-twobase10 [J_A_Sever] [J_A_Sever]
25010-25099 Unassigned
db2c-tls 25100 tcp IBM Db2 Client Interface - Encrypted [IBM] [Matthew_Emmerton] 2024-03-05
25100 udp Reserved
25101-25470 Unassigned
rna 25471 sctp RNSAP User Adaptation for Iurh [Dario_S_Tonesi] [Dario_S_Tonesi] 2011-02-07
niobserver 25901 tcp NIObserver [Roman_Oliynyk] [Roman_Oliynyk]
niobserver 25901 udp NIObserver [Roman_Oliynyk] [Roman_Oliynyk]
26001-26132 Unassigned
scscp 26133 tcp Symbolic Computation Software Composability Protocol [Alexander_Konovalov] [Alexander_Konovalov] 2007-11-27
scscp 26133 udp Symbolic Computation Software Composability Protocol [Alexander_Konovalov] [Alexander_Konovalov] 2007-11-27
26134-26207 Unassigned
ezmeeting 26261 tcp eZmeeting [Albert_C_Yang] [Albert_C_Yang]
ezmeeting 26261 udp eZmeeting [Albert_C_Yang] [Albert_C_Yang]
flex-lm 27000-27009 FLEX LM (1-10) [Flexera_Software] [Paul_Bland] 2018-02-15
flex-lmadmin 27010 tcp A protocol for managing license services [Flexera] [Paul_Bland] 2018-08-22
27010 udp Reserved
27011-27015 Unassigned
chlenix 27016 tcp Cloud hosting environment network [Vlad_Bondarenko] [Vlad_Bondarenko] 2024-09-23
27016 udp Reserved
mongodb 27017 tcp Mongo database system [MongoDB_Inc.] [Akshay_Kumar] 2019-02-21
27017 udp Reserved
27018-27344 Unassigned Unauthorized Use Known on ports 27018 and 27019
27346-27441 Unassigned
27505-27781 Unassigned
pqsp 28001 tcp PQ Service [Peter_Laschtowitz] [Peter_Laschtowitz] 2009-09-15
28001 udp Reserved
gruber-cashreg 28010 tcp Gruber cash registry protocol [Gruber_Schanksysteme] [Clemens_Gruber] 2019-12-31
28010 udp Reserved
28011-28079 Unassigned Unauthorized Use Known on ports 28017, 28018 and 28019
28081-28118 Unassigned
28119 tcp Reserved
a27-ran-ran 28119 udp A27 cdma2000 RAN Management [_3GPP_2] [Zhiming_Li] 2012-04-13
28120-28199 Unassigned
28201-28239 Unassigned
28241-28588 Unassigned
29001-29117 Unassigned
29118 tcp Reserved
29118 udp Reserved
sgsap 29118 sctp SGsAP in 3GPP [_3GPP_Specifications] [_3GPP_Specifications] 2009-06-11
29119-29166 Unassigned
otmp 29167 tcp ObTools Message Protocol [Paul_Clark] [Paul_Clark] 2006-02
otmp 29167 udp ObTools Message Protocol [Paul_Clark] [Paul_Clark] 2006-02
29168 tcp Reserved
29168 udp Reserved
sbcap 29168 sctp SBcAP in 3GPP [_3GPP_Specifications] [_3GPP_Specifications] 2009-06-11
iuhsctpassoc 29169 sctp HNBAP and RUA Common Association [Dongwook_Kim] [Dongwook_Kim] 2009-09-08 2026-01-23
29170-29998 Unassigned
bingbang 29999 tcp data exchange protocol for IEC61850 in wind power plants [DEIF_AS] [Armin_Solies] 2012-10-15
pago-services1 30001 tcp Pago Services 1 [Balduin_Mueller_Plat] [Balduin_Mueller_Plat] 2002-03
pago-services1 30001 udp Pago Services 1 [Balduin_Mueller_Plat] [Balduin_Mueller_Plat] 2002-03
rwp 30100 tcp Remote Window Protocol [Maxim_Baklanovsky] [Maxim_Baklanovsky] 2015-05-20
30100 udp Reserved
rwp 30100 sctp Remote Window Protocol [Maxim_Baklanovsky] [Maxim_Baklanovsky] 2015-05-20
30101-30259 Unassigned

Contact Information

ID Name Organization Contact URI Last Updated
[_3GPP_2] 3GPP2 mailto:lizhiming&huawei.com 2012-01-11
[Akshay_Kumar] Akshay Kumar MongoDB, Inc. mailto:akshay&mongodb.com 2019-02-21
[Albert_C_Yang] Albert C. Yang mailto:albert.yang&ezmeeting.com 2002-03
[Alexander_Konovalov] Alexander Konovalov mailto:konovalov&member.ams.org 2007-11-27
[Armin_Solies] Armin Solies DEIF A/S mailto:aes&deif.com 2012-10-15
[Balduin_Mueller_Plat] Balduin Mueller-Platz mailto:balduin.mueller-platz&pago.de 2002-03
[Chris_Koeritz_3] Chris Koeritz mailto:portmanager&inovasolutions.com 2006-10
[Christoph_Anton_Mitt] Christoph Anton Mitterer mailto:calestyo&scientia.net 2009-03-10
[Clemens_Gruber] Clemens Gruber mailto:iana&pqgruber.com 2019-12-31
[Dario_S_Tonesi] Dario S. Tonesi mailto:dario.tonesi&nsn.com 2011-02-07
[DEIF_AS] DEIF A/S mailto:aes&deif.com 2012-10-15
[Dongwook_Kim] Dongwook Kim 3GPP mailto:dongwook.kim&etsi.org 2026-01-23
[Flexera] Flexera mailto:pbland&flexera.com 2018-08-22
[Flexera_Software] Flexera Software mailto:security&flexerasoftware.com 2016-07-19
[_3GPP_Specifications] Dongwook Kim 3GPP Specifications Manager mailto:dongwook.kim&etsi.org 2026-01-23
[Gruber_Schanksysteme] Gruber Schanksysteme mailto:iana&pqgruber.com 2019-12-31
[IBM] IBM mailto:memmerto&ca.ibm.com 2024-03-05
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[J_A_Sever] J. A. (Tony) Sever mailto:J.A.Sever&bra0119.wins.icl.co.uk
[Juergen_Fischbach] Juergen Fischbach mailto:juergen.fischbach&philips.com
[Keith_Kilroy] Keith Kilroy mailto:Keith.Kilroy&novarcontrols.com 2006-02
[Kevin_Kuhns] Kevin Kuhns mailto:kkuhns&opto22.com
[Kimmo_Kymalainen] Kimmo Kymalainen mailto:kimmo.kymalainen&etsi.org 2017-05-08
[Matthew_Emmerton] Matthew Emmerton IBM mailto:memmerto&ca.ibm.com 2024-03-05
[Maxim_Baklanovsky] Maxim Baklanovsky mailto:m.baklanovsky&spbu.ru 2015-05-20
[Mitchell_Bass] Mitchell Bass mailto:mitch&integrasolv.com 2005-08
[MongoDB_Inc.] MongoDB, Inc. mailto:akshay&mongodb.com 2019-02-21
[Paul_Bland] Paul Bland mailto:pbland&flexera.com 2018-08-22
[Paul_Clark] Paul Clark mailto:paul&xmill.com 2006-02
[Peter_Laschtowitz] Peter Laschtowitz mailto:pl&pq-computers.de 2009-09-15
[Roman_Oliynyk] Roman Oliynyk mailto:romano&netinst.com
[Timo_Sivonen] Timo Sivonen mailto:timo.sivonen&ccmail.dowjones.com
[Toby_Hosterman] Toby Hosterman mailto:root&netspeak.com
[Vlad_Bondarenko] Vlad Bondarenko mailto:bondarenko.vlad.univ&gmail.com 2024-09-23
[WIBU-SYSTEMS_AG] WIBU-SYSTEMS AG mailto:oliver.winzenried&wibu.com 2013-06-25
[Wolfgang_Völker_2] Wolfgang Völker WIBU-SYSTEMS AG mailto:wolfgang.voelker&wibu.com 2013-06-25
[Zhiming_Li] Zhiming Li 3GPP2 mailto:lizhiming&huawei.com 2012-01-11