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
dls-mon 198 tcp Directory Location Service Monitor [Scott_Bellew] [Scott_Bellew]
dls-mon 198 udp Directory Location Service Monitor [Scott_Bellew] [Scott_Bellew]
cajo-discovery 1198 tcp cajo reference discovery [John_Catherino] [John_Catherino] 2005-08
cajo-discovery 1198 udp cajo reference discovery [John_Catherino] [John_Catherino] 2005-08
panquest-xact 1980 tcp PanQuest XACT [Chris_Vertonghen] [Chris_Vertonghen] 2025-11-20
panquest-xact 1980 udp PanQuest XACT [Chris_Vertonghen] [Chris_Vertonghen] 2025-11-20
p2pq 1981 tcp p2pQ [Warren_Alexander] [Warren_Alexander]
p2pq 1981 udp p2pQ [Warren_Alexander] [Warren_Alexander]
estamp 1982 tcp Evidentiary Timestamp [Todd_Glassey] [Todd_Glassey]
estamp 1982 udp Evidentiary Timestamp [Todd_Glassey] [Todd_Glassey]
lhtp 1983 tcp Loophole Test Protocol [Kade_Hansson] [Kade_Hansson]
lhtp 1983 udp Loophole Test Protocol [Kade_Hansson] [Kade_Hansson]
bb 1984 tcp BB [Sean_MacGuire] [Sean_MacGuire]
bb 1984 udp BB [Sean_MacGuire] [Sean_MacGuire]
hsrp 1985 tcp Hot Standby Router Protocol [RFC2281]
hsrp 1985 udp Hot Standby Router Protocol [RFC2281]
licensedaemon 1986 tcp cisco license management
licensedaemon 1986 udp cisco license management
tr-rsrb-p1 1987 tcp cisco RSRB Priority 1 port
tr-rsrb-p1 1987 udp cisco RSRB Priority 1 port
tr-rsrb-p2 1988 tcp cisco RSRB Priority 2 port
tr-rsrb-p2 1988 udp cisco RSRB Priority 2 port
tr-rsrb-p3 1989 tcp cisco RSRB Priority 3 port
tr-rsrb-p3 1989 udp cisco RSRB Priority 3 port
mshnet 1989 tcp MHSnet system [Bob_Kummerfeld] [Bob_Kummerfeld] This entry records an unassigned but widespread use
mshnet 1989 udp MHSnet system [Bob_Kummerfeld] [Bob_Kummerfeld] This entry records an unassigned but widespread use
onehome-remote 2198 tcp OneHome Remote Access
onehome-remote 2198 udp OneHome Remote Access
embrace-dp-c 3198 tcp Embrace Device Protocol Client [Elliot_Schwartz] [Elliot_Schwartz]
embrace-dp-c 3198 udp Embrace Device Protocol Client [Elliot_Schwartz] [Elliot_Schwartz]
4198 Unassigned
dtn-bundle 4556 dccp DTN Bundle DCCP CL Protocol 2013-11-12 2014-02-21 [RFC7122] 1685351985
5198-5199 Unassigned
8196-8198 Unassigned

Contact Information

ID Name Contact URI Last Updated
[Bob_Kummerfeld] Bob Kummerfeld mailto:bob&sarad.cs.su.oz.au
[Chris_Vertonghen] Chris Vertonghen mailto:chris&panquest.com 2025-11-20
[Elliot_Schwartz] Elliot Schwartz mailto:elliot&mit.edu
[John_Catherino] John Catherino mailto:cajo&dev.java.net 2005-08
[Kade_Hansson] Kade Hansson mailto:kade_fh&postoffice.utas.edu.au
[Scott_Bellew] Scott Bellew mailto:smb&cs.purdue.edu
[Sean_MacGuire] Sean MacGuire mailto:sean&maclawran.ca
[Todd_Glassey] Todd Glassey mailto:todd.glassey&att.net
[Warren_Alexander] Warren Alexander mailto:warren&chameleon-creative.co.uk