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
dnp-sec 19999 tcp Distributed Network Protocol - Secure [Grant_Gilchrist] [Grant_Gilchrist] 2008-08-04
dnp-sec 19999 udp Distributed Network Protocol - Secure [Grant_Gilchrist] [Grant_Gilchrist] 2008-08-04
dnp-sec 19999 sctp Distributed Network Protocol - secured [DNP_Users_Group] [Andrew_West] 2022-12-20
20811-20998 Unassigned
athand-mmp 20999 tcp At Hand MMP [Stepan_Riha] [Stepan_Riha]
athand-mmp 20999 udp AT Hand MMP [Stepan_Riha] [Stepan_Riha]
21591-21799 Unassigned
21850-21999 Unassigned
22764-22799 Unassigned
22952-22999 Unassigned
23334-23399 Unassigned
23547-23999 Unassigned
udpstp 24601 udp UDP-based IP-Layer Capacity and Performance Measurement protocol [IESG] [IETF_Chair] 2025-09-26 [RFC9946]
24923-24999 Unassigned
25010-25099 Unassigned
25794-25899 Unassigned
25956-25999 Unassigned
26490-26999 Unassigned
27877-27998 Unassigned
tw-auth-key 27999 tcp TW Authentication/Key Distribution and [Alex_Duncan_2] [Alex_Duncan_2]
tw-auth-key 27999 udp Attribute Certificate Services [Alex_Duncan_2] [Alex_Duncan_2]
28120-28199 Unassigned
28590-28999 Unassigned
29170-29998 Unassigned
bingbang 29999 tcp data exchange protocol for IEC61850 in wind power plants [DEIF_AS] [Armin_Solies] 2012-10-15
29999 udp Reserved
30005-30099 Unassigned
30261-30399 Unassigned
30940-30998 Unassigned
ovobs 30999 tcp OpenView Service Desk Client [Service_Desk_Product] [Service_Desk_Product] 2006-05
ovobs 30999 udp OpenView Service Desk Client [Service_Desk_Product] [Service_Desk_Product] 2006-05
31338-31399 Unassigned
32250-32399 Unassigned
32897-32999 Unassigned
34981-34999 Unassigned
35007-35099 Unassigned
36603-36699 Unassigned
37655-37999 Unassigned
38639-38799 Unassigned
39682-39999 Unassigned
42511-42998 Unassigned
curiosity 42999 tcp API endpoint for search application [Curiosity_GmbH] [Rafael_Fernandes_de_Oliveira] 2022-12-09
42999 udp Reserved
44554-44599 Unassigned
44819-44899 Unassigned
44901-44999 Unassigned
46337-46997 Unassigned
spremotetablet 46998 tcp Connection between a desktop computer or server and a signature tablet to capture handwritten signatures [SOFTPRO_GmbH] [Christoph_Hipp] 2012-07-19 2013-08-02
46998 udp Reserved
mediabox 46999 tcp MediaBox Server [Alexander_Graef] [Alexander_Graef] 2004-11
mediabox 46999 udp MediaBox Server [Alexander_Graef] [Alexander_Graef] 2004-11
47002-47099 Unassigned
47810-47999 Unassigned
48654-48999 Unassigned
netconf-beep NETCONF over BEEP [RFC4744][RFC9900]
netconfsoapbeep NETCONF for SOAP over BEEP [RFC4743][RFC9900]
netconfsoaphttp NETCONF for SOAP over HTTPS [RFC4743][RFC9900]
brski-proxy tcp The Bootstrapping Remote Secure Key Infrastructure Proxy [IESG] [IETF_Chair] 2020-04-29 [RFC8995] Defined TXT keys: None
brski-registrar tcp The Bootstrapping Remote Secure Key Infrastructure Registrar [IESG] [IETF_Chair] 2020-04-29 [RFC8995] Defined TXT keys: None

Contact Information

ID Name Organization Contact URI Last Updated
[Alex_Duncan_2] Alex Duncan mailto:Alex.Duncan&sse.ie
[Alexander_Graef] Alexander Graef mailto:alex&graef.cc 2004-11
[Andrew_West] Andrew West mailto:andrew.west&ieee.org 2022-12-20
[Armin_Solies] Armin Solies DEIF A/S mailto:aes&deif.com 2012-10-15
[Christoph_Hipp] Christoph Hipp SOFTPRO GmbH mailto:christoph.hipp&softpro.de 2013-08-02
[Curiosity_GmbH] Curiosity GmbH mailto:hello&curiosity.ai 2022-12-09
[DEIF_AS] DEIF A/S mailto:aes&deif.com 2012-10-15
[DNP_Users_Group] DNP Users Group mailto:chair_tech&dnp.org 2022-12-20
[Grant_Gilchrist] Grant Gilchrist mailto:grant&enernex.com 2010-10-18
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Rafael_Fernandes_de_Oliveira] Rafael Fernandes de Oliveira mailto:rafael&curiosity.ai 2022-12-09
[Service_Desk_Product] Service Desk Product Manager mailto:info&hp.com 2006-05
[SOFTPRO_GmbH] SOFTPRO GmbH mailto:christoph.hipp&softpro.de 2013-08-02
[Stepan_Riha] Stepan Riha mailto:stepan.riha&hand.com