Service Name and Transport Protocol Port Number Registry

Last Updated
2026-09-11
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
nntps 563 tcp nntp protocol over TLS/SSL (was snntp) [IESG] [IETF_Chair] 2018-07-06 [RFC4642]
nntps 563 udp nntp protocol over TLS/SSL (was snntp) [IESG] [IETF_Chair] 2018-07-06 [RFC4642]
esro-emsdp 642 tcp ESRO-EMSDP V1.3 [Mohsen_Banan_2] [Mohsen_Banan_2]
esro-emsdp 642 udp ESRO-EMSDP V1.3 [Mohsen_Banan_2] [Mohsen_Banan_2]
isis-am 1642 tcp isis-am
isis-am 1642 udp isis-am
tragic 2642 tcp Tragic [Stu_Mark] [Stu_Mark]
tragic 2642 udp Tragic [Stu_Mark] [Stu_Mark]
juxml-port 3642 tcp Juxml Replication port [Colin_Reid] [Colin_Reid] 2002-11
juxml-port 3642 udp Juxml Replication port [Colin_Reid] [Colin_Reid] 2002-11
nim-vdrshell 6420 tcp NIM_VDRShell [Rik_Ditter] [Rik_Ditter] 2006-02
nim-vdrshell 6420 udp NIM_VDRShell [Rik_Ditter] [Rik_Ditter] 2006-02
nim-wan 6421 tcp NIM_WAN [Rik_Ditter] [Rik_Ditter] 2006-02
nim-wan 6421 udp NIM_WAN [Rik_Ditter] [Rik_Ditter] 2006-02
6422-6431 Unassigned
36413-36421 Unassigned
36422 tcp Reserved
36422 udp Reserved
x2-control 36422 sctp X2-Control Plane (3GPP) [Kimmo_Kymalainen] [Kimmo_Kymalainen] 2009-09-01
slmap 36423 sctp SLm Interface Application Protocol [_3GPP_4] [Kimmo_Kymalainen] 2015-06-18
nq-ap 36424 sctp Nq and Nq' Application Protocol [_3GPP_4] [Kimmo_Kymalainen] 2015-06-18
36425-36442 Unassigned

Contact Information

ID Name Organization Contact URI Last Updated
[_3GPP_4] 3GPP mailto:kimmo.kymalainen&etsi.org 2015-06-18
[Colin_Reid] Colin Reid mailto:creid&projux.com 2002-11
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Kimmo_Kymalainen] Kimmo Kymalainen mailto:kimmo.kymalainen&etsi.org 2017-05-08
[Mohsen_Banan_2] Mohsen Banan mailto:mohsen&neda.com
[Rik_Ditter] Rik Ditter mailto:managers&generationtechnologies.com 2006-02
[Stu_Mark] Stu Mark mailto:fordii&j51.com