Service Name and Transport Protocol Port Number Registry

Last Updated
2026-09-07
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
hks-lm 1722 tcp HKS License Manager [Michael_Wood] [Michael_Wood]
hks-lm 1722 udp HKS License Manager [Michael_Wood] [Michael_Wood]
11721-11722 Unassigned
avtp 17220 tcp IEEE 1722 Transport Protocol for Time Sensitive Applications [Transport_Protocol_for_Time-Sensitive_Networking_TG] [Ashley_Butterworth] 2014-03-07
avtp 17220 udp IEEE 1722 Transport Protocol for Time Sensitive Applications [Transport_Protocol_for_Time-Sensitive_Networking_TG] [Ashley_Butterworth] 2014-03-07
avdecc 17221 tcp IEEE 1722.1 AVB Discovery, Enumeration, Connection management, and Control [IEEE_1722_1] [Jeffrey_Daniel_Koftinoff] 2011-11-01
avdecc 17221 udp IEEE 1722.1 AVB Discovery, Enumeration, Connection management, and Control [IEEE_1722_1] [Jeffrey_Daniel_Koftinoff] 2011-11-01
17222 tcp Reserved
cpsp 17222 udp Control Plane Synchronization Protocol (SPSP) [Randall_Stewart_2] [Randall_Stewart_2] 2011-11-10
isa100-gci 17223 tcp ISA100 GCI is a service utilizing a common interface between an ISA100 Wireless gateway and a client application [ISA100_Wireless_Compliance_Institute] [Jay_Werb] 2015-07-24
17223 udp Reserved
trdp-pd 17224 udp Train Realtime Data Protocol (TRDP) Process Data [IEC_Central_Office] [Gianosvaldo_Fadin] 2015-07-24
17224 tcp Reserved
trdp-md 17225 tcp Train Realtime Data Protocol (TRDP) Message Data [IEC_Central_Office] [Gianosvaldo_Fadin] 2015-07-24
trdp-md 17225 udp Train Realtime Data Protocol (TRDP) Message Data [IEC_Central_Office] [Gianosvaldo_Fadin] 2015-07-24
17226-17233 Unassigned

Contact Information

ID Name Organization Contact URI Last Updated
[Ashley_Butterworth] Ashley Butterworth mailto:abutterworth&apple.com 2014-03-07
[Gianosvaldo_Fadin] Gianosvaldo Fadin IEC Central Office mailto:gianosvaldo.fadin&anie.it 2015-07-24
[IEEE_1722_1] IEEE-1722.1 mailto:jeff.koftinoff&ieee.com 2011-11-01
[IEC_Central_Office] IEC Central Office mailto:cj&iec.ch 2015-07-24
[ISA100_Wireless_Compliance_Institute] ISA100 Wireless Compliance Institute mailto:jay&jwerb.com 2015-07-24
[Jay_Werb] Jay Werb ISA100 Wireless Compliance Institute mailto:jay&jwerb.com 2015-07-24
[Jeffrey_Daniel_Koftinoff] Jeffrey Daniel Koftinoff IEEE-1722.1 mailto:jeff.koftinoff&ieee.com 2011-11-01
[Michael_Wood] Michael Wood mailto:wood&althea.hks.com
[Randall_Stewart_2] Randall Stewart mailto:rrs&lakerest.net 2011-10-24
[Transport_Protocol_for_Time-Sensitive_Networking_TG] Transport Protocol for Time-Sensitive Networking TG mailto:AVBTP&ieee.org 2014-03-07