Service Name and Transport Protocol Port Number Registry

Last Updated
2026-09-11
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
pssc 645 tcp PSSC [Egon_Meier_Engelen] [Egon_Meier_Engelen]
pssc 645 udp PSSC [Egon_Meier_Engelen] [Egon_Meier_Engelen]
sightline 1645 tcp SightLine [admin] [admin]
sightline 1645 udp SightLine [admin] [admin]
novell-ipx-cmd 2645 tcp Novell IPX CMD [Juan_Carlos_Luciani] [Juan_Carlos_Luciani]
novell-ipx-cmd 2645 udp Novell IPX CMD [Juan_Carlos_Luciani] [Juan_Carlos_Luciani]
cyc 3645 tcp Cyc [Stephen_Reed] [Stephen_Reed] 2003-01
cyc 3645 udp Cyc [Stephen_Reed] [Stephen_Reed] 2003-01
4622-4645 Unassigned
5640-5645 Unassigned
6447-6454 Unassigned
skip-cert-recv 6455 tcp SKIP Certificate Receive [Tom_Markson] [Tom_Markson]
skip-cert-recv 6455 udp SKIP Certificate Receive [Tom_Markson] [Tom_Markson]
skip-cert-send 6456 tcp SKIP Certificate Send [Tom_Markson] [Tom_Markson]
skip-cert-send 6456 udp SKIP Certificate Send [Tom_Markson] [Tom_Markson]
6457-6463 Unassigned
multicast-ping 9903 udp Multicast Ping Protocol 2011-12-09 [RFC6450]

Contact Information

ID Name Contact URI Last Updated
[Egon_Meier_Engelen] Egon Meier-Engelen mailto:egon.meier-engelen&dlr.de
[Juan_Carlos_Luciani] Juan Carlos Luciani mailto:jluciani&novell.com
[Stephen_Reed] Stephen Reed mailto:reed&cyc.com 2003-01
[Tom_Markson] Tom Markson mailto:markson&osmosys.incog.com
[admin] admin mailto:iana&sightlinesystems.com