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
ncp 524 tcp NCP [Don_Provan_2] [Don_Provan_2]
ncp 524 udp NCP [Don_Provan_2] [Don_Provan_2]
ingreslock 1524 tcp ingres
ingreslock 1524 udp ingres
optiwave-lm 2524 tcp Optiwave License Management [Slawomir_Krzesinski] [Slawomir_Krzesinski]
optiwave-lm 2524 udp Optiwave License Management [Slawomir_Krzesinski] [Slawomir_Krzesinski]
ecmport 3524 tcp ECM Server port
ecmport 3524 udp ECM Server port
krb524 4444 tcp KRB524 [B_Clifford_Neuman] [B_Clifford_Neuman] krb524 assigned the port, nv used it without an assignment
krb524 4444 udp KRB524 [B_Clifford_Neuman] [B_Clifford_Neuman] krb524 assigned the port, nv used it without an assignment
nv-video 4444 tcp NV Video default [Ron_Frederick] [Ron_Frederick] krb524 assigned the port, nv used it without an assignment
nv-video 4444 udp NV Video default [Ron_Frederick] [Ron_Frederick] krb524 assigned the port, nv used it without an assignment
5238-5241 Unassigned
attune 5242 tcp ATTUne API [Bellvedi_Ltd] [Sean_D_Sollé_2] 2022-06-01
5242 udp Reserved
xycstatus 5243 tcp xyClient Status API and rendevous point [Xycare_Ltd] [Luke_Bailey] 2022-06-06
5243 udp Reserved
5244 Unassigned
downtools 5245 tcp DownTools Control Protocol [Jarrod_Sayers] [Jarrod_Sayers] 2009-04-07
downtools-disc 5245 udp DownTools Discovery Protocol [Jarrod_Sayers] [Jarrod_Sayers] 2009-04-07
5246 tcp Reserved
capwap-control 5246 udp CAPWAP Control Protocol [RFC5415]
5247 tcp Reserved
capwap-data 5247 udp CAPWAP Data Protocol [RFC5415]
caacws 5248 tcp CA Access Control Web Service [Gabriel_Kalmar] [Gabriel_Kalmar] 2008-03-06
caacws 5248 udp CA Access Control Web Service [Gabriel_Kalmar] [Gabriel_Kalmar] 2008-03-06
caaclang2 5249 tcp CA AC Lang Service [Gabriel_Kalmar] [Gabriel_Kalmar] 2008-02-19
caaclang2 5249 udp CA AC Lang Service [Gabriel_Kalmar] [Gabriel_Kalmar] 2008-02-19
febooti-aw 36524 tcp Febooti Automation Workshop [Maris_Bormanis] [Maris_Bormanis] 2011-06-10
36524 udp Reserved

Contact Information

ID Name Organization Contact URI Last Updated
[B_Clifford_Neuman] B. Clifford Neuman mailto:bcn&isi.edu 2022-02-18
[Bellvedi_Ltd] Bellvedi Ltd. mailto:iana&bellvedi.com 2022-06-01
[Don_Provan_2] Don Provan mailto:donp&sjf.novell.com
[Gabriel_Kalmar] Gabriel Kalmar mailto:kalga01&ca.com 2008-03-06
[Jarrod_Sayers] Jarrod Sayers mailto:jarrod&downtools.com.au 2009-04-07
[Luke_Bailey] Luke Bailey Xycare Ltd mailto:luke.bailey&xycare.co.uk 2022-06-06
[Maris_Bormanis] Maris Bormanis mailto:info&febooti.com 2011-06-10
[Ron_Frederick] Ron Frederick mailto:frederick&parc.xerox.com
[Sean_D_Sollé_2] Sean D. Sollé Bellvedi Ltd. mailto:iana&bellvedi.com 2022-06-01
[Slawomir_Krzesinski] Slawomir Krzesinski mailto:slavek&optiwave.com
[Xycare_Ltd] Xycare Ltd mailto:luke.bailey&xycare.co.uk 2022-06-06