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
ipcd 576 tcp ipcd
ipcd 576 udp ipcd
moldflow-lm 1576 tcp Moldflow License Manager [Lech_Laskowski] [Lech_Laskowski]
moldflow-lm 1576 udp Moldflow License Manager [Lech_Laskowski] [Lech_Laskowski]
tclprodebugger 2576 tcp TCL Pro Debugger
tclprodebugger 2576 udp TCL Pro Debugger
cmc-port 3576 tcp Coalsere CMC Port [Chris_Hawkinson] [Chris_Hawkinson] 2002-08
cmc-port 3576 udp Coalsere CMC Port [Chris_Hawkinson] [Chris_Hawkinson] 2002-08
radius-dynauth 3799 tcp RADIUS Dynamic Authorization [RFC3576]
radius-dynauth 3799 udp RADIUS Dynamic Authorization [RFC3576]
avt-profile-1 5004 dccp RTP media data [RFC3551][RFC5762]
avt-profile-2 5005 dccp RTP control protocol [RFC3551][RFC5762]
5576-5578 Unassigned
5758-5765 Unassigned
openmailns 5766 tcp OpenMail NewMail Server [OpenMail_Encyclopedi][Don_Loughry] [OpenMail_Encyclopedi][Don_Loughry]
openmailns 5766 udp OpenMail NewMail Server [OpenMail_Encyclopedi][Don_Loughry] [OpenMail_Encyclopedi][Don_Loughry]
s-openmail 5767 tcp OpenMail Suer Agent Layer (Secure) [OpenMail_Encyclopedi][Don_Loughry] [OpenMail_Encyclopedi][Don_Loughry]
s-openmail 5767 udp OpenMail Suer Agent Layer (Secure) [OpenMail_Encyclopedi][Don_Loughry] [OpenMail_Encyclopedi][Don_Loughry]
openmailpxy 5768 tcp OpenMail CMTS Server [OpenMail_Encyclopedi][Don_Loughry] [OpenMail_Encyclopedi][Don_Loughry]
openmailpxy 5768 udp OpenMail CMTS Server [OpenMail_Encyclopedi][Don_Loughry] [OpenMail_Encyclopedi][Don_Loughry]
spramsca 5769 tcp x509solutions Internal CA [Brendan_Fay] [Brendan_Fay] 2006-02
spramsca 5769 udp x509solutions Internal CA [Brendan_Fay] [Brendan_Fay] 2006-02
7576-7587 Unassigned
24555-24576 Unassigned
sauterdongle 25576 tcp Sauter Dongle [Christian_Brecht] [Christian_Brecht] 2010-12-15
25576 udp Reserved

Contact Information

ID Name Organization Contact URI Last Updated
[Brendan_Fay] Brendan Fay mailto:brendan.fay&x509solutions.com 2006-02
[Chris_Hawkinson] Chris Hawkinson mailto:chawkinson&coalsere.com 2002-08
[Christian_Brecht] Christian Brecht mailto:Christian.Brecht&sauter-gmbh.de 2010-12-15
[Don_Loughry] Don Loughry mailto:DON_LOUGHRY&hp-cupertino-om4.om.hp.com
[Lech_Laskowski] Lech Laskowski mailto:lech_laskowski&moldflow.com
[OpenMail_Encyclopedi] OpenMail Encyclopedia mailto:opencyc&hpopd.pwd.hp.com