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
qmqp 628 tcp QMQP [D_J_Bernstein] [D_J_Bernstein] 2018-04-05
qmqp 628 udp QMQP [D_J_Bernstein] [D_J_Bernstein] 2018-04-05
lontalk-norm 1628 tcp LonTalk normal
lontalk-norm 1628 udp LonTalk normal
dict 2628 tcp DICT [Rik_Faith] [Rik_Faith]
dict 2628 udp DICT [Rik_Faith] [Rik_Faith]
ept-machine 3628 tcp EPT Machine Interface [Victor_H_Farrace] [Victor_H_Farrace] 2002-10
ept-machine 3628 udp EPT Machine Interface [Victor_H_Farrace] [Victor_H_Farrace] 2002-10
htrust 5628 tcp HTrust API [Karl_Olafsson] [Karl_Olafsson] 2008-10-24
htrust 5628 udp HTrust API [Karl_Olafsson] [Karl_Olafsson] 2008-10-24
afesc-mc 6628 tcp AFE Stock Channel M/C [K_K_Ho] [K_K_Ho] 2004-04
afesc-mc 6628 udp AFE Stock Channel M/C [K_K_Ho] [K_K_Ho] 2004-04
zen-pawn 7628 tcp Primary Agent Work Notification [Ty_Ellis] [Ty_Ellis] 2006-05
zen-pawn 7628 udp Primary Agent Work Notification [Ty_Ellis] [Ty_Ellis] 2006-05
odbcpathway 9628 tcp ODBC Pathway Service [Adrian_Hungate] [Adrian_Hungate] 2007-05
odbcpathway 9628 udp ODBC Pathway Service [Adrian_Hungate] [Adrian_Hungate] 2007-05
autotunnel udp IPSEC VPN tunnel over UDP [Stuart_Cheshire] [Stuart_Cheshire] 2019-05-04 [RFC6281] Defined TXT Keys: None
dns-llq-tls tcp DNS Long-Lived Queries over TLS [Stuart_Cheshire] [Stuart_Cheshire] 2019-05-04 [RFC6281] Defined TXT Keys: None
dns-update-tls tcp DNS Dynamic Update Service over TLS [Stuart_Cheshire] [Stuart_Cheshire] 2019-05-04 [RFC6281] DNS Dynamic Update Service for a given domain may not necessarily be provided by the principal name servers as advertised by the domain's "NS" records, and may not necessarily always be provided on port 53. The "_dns-update._udp.<domain>." SRV record gives the target host and port where DNS Dynamic Update Service is provided for the named domain.

Contact Information

ID Name Contact URI Last Updated
[Adrian_Hungate] Adrian Hungate mailto:adrian&tlspu.com 2014-07-11
[D_J_Bernstein] D. J. Bernstein mailto:ports&box.cr.yp.to 2018-04-05
[K_K_Ho] K. K Ho mailto:kk.ho&afe-solutions.com 2004-04
[Karl_Olafsson] Karl Olafsson mailto:Karl.Olafsson&covariant-systems.com 2008-10-24
[Rik_Faith] Rik Faith mailto:faith&cs.unc.edu
[Stuart_Cheshire] Stuart Cheshire mailto:cheshire&apple.com 2022-07-11
[Ty_Ellis] Ty Ellis mailto:tellis&novell.com 2006-05
[Victor_H_Farrace] Victor H. Farrace mailto:vfarrace&eaglept.com 2002-10