Service Name and Transport Protocol Port Number Registry

Last Updated
2026-09-02
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
ldp 646 tcp LDP [Bob_Thomas] [Bob_Thomas]
ldp 646 udp LDP [Bob_Thomas] [Bob_Thomas]
sa-msg-port 1646 tcp sa-msg-port [Eric_Whitehill] [Eric_Whitehill]
sa-msg-port 1646 udp sa-msg-port [Eric_Whitehill] [Eric_Whitehill]
and-lm 2646 tcp AND License Manager [Dick_van_der_Sijs] [Dick_van_der_Sijs]
and-lm 2646 udp AND License Manager [Dick_van_der_Sijs] [Dick_van_der_Sijs]
xss-srv-port 3646 tcp XSS Server Port [Joe_Purcell] [Joe_Purcell] 2003-01
xss-srv-port 3646 udp XSS Server Port [Joe_Purcell] [Joe_Purcell] 2003-01
dots-signal 4646 tcp Distributed Denial-of-Service Open Threat Signaling (DOTS) Signal Channel Protocol. The service name is used to construct the SRV service names "_dots-signal._udp" and "_dots-signal._tcp" for discovering DOTS servers used to establish DOTS signal channel. [IESG] [IETF_Chair] 2020-01-16 2021-06-14 [RFC8973][RFC9132]
dots-signal 4646 udp Distributed Denial-of-Service Open Threat Signaling (DOTS) Signal Channel Protocol. The service name is used to construct the SRV service names "_dots-signal._udp" and "_dots-signal._tcp" for discovering DOTS servers used to establish DOTS signal channel. [IESG] [IETF_Chair] 2020-01-16 2021-06-14 [RFC8973][RFC9132]
vfmobile 5646 tcp Ventureforth Mobile [Ventureforth_Inc] [Blakely_Snyder] 2011-11-03
5646 udp Reserved
6457-6463 Unassigned
ieee11073-20701 6464 tcp Port assignment for medical device communication in accordance to IEEE 11073-20701 [David_Gregorczyk] [David_Gregorczyk] 2017-03-02
ieee11073-20701 6464 udp Port assignment for medical device communication in accordance to IEEE 11073-20701 [David_Gregorczyk] [David_Gregorczyk] 2017-03-02
6465-6470 Unassigned
36445-36461 Unassigned
36462 tcp Reserved
36462 udp Reserved
xw-control 36462 sctp Xw-Control Plane (3GPP) [Boubacar_KIMNBA_DIT_ADAMOU] [Boubacar_KIMNBA_DIT_ADAMOU] 2015-11-13
36463-36523 Unassigned

Contact Information

ID Name Organization Contact URI Last Updated
[Blakely_Snyder] Blakely Snyder Ventureforth Inc. mailto:bsnyder&ventureforth.com 2011-11-03
[Bob_Thomas] Bob Thomas mailto:rhthomas&cisco.com
[Boubacar_KIMNBA_DIT_ADAMOU] Boubacar KIMNBA DIT ADAMOU mailto:jinba&chinamobile.com 2015-11-13
[David_Gregorczyk] David Gregorczyk mailto:david.gregorczyk&draeger.com 2017-03-02
[Dick_van_der_Sijs] Dick van der Sijs mailto:dick&and.nl
[Eric_Whitehill] Eric Whitehill mailto:Eric.Whitehill&itt.com
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Joe_Purcell] Joe Purcell mailto:jpurcell&ensuretech.com 2003-01
[Ventureforth_Inc] Ventureforth Inc. mailto:support&ventureforth.com 2011-11-03