Service Name and Transport Protocol Port Number Registry

Last Updated
2026-09-07
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
ocs-cmu 428 tcp OCS_CMU

IANA assigned this well-formed service name as a replacement for "ocs_cmu".
ocs_cmu 428 tcp OCS_CMU This entry is an alias to "ocs-cmu". This entry is now historic, not usable for use with many common service discovery mechanisms.
ocs-cmu 428 udp OCS_CMU

IANA assigned this well-formed service name as a replacement for "ocs_cmu".
ocs_cmu 428 udp OCS_CMU This entry is an alias to "ocs-cmu". This entry is now historic, not usable for use with many common service discovery mechanisms.
informatik-lm 1428 tcp Informatik License Manager [Harald_Schlangmann] [Harald_Schlangmann]
informatik-lm 1428 udp Informatik License Manager [Harald_Schlangmann] [Harald_Schlangmann]
ott 2428 tcp One Way Trip Time [Greg_Troxel] [Greg_Troxel]
ott 2428 udp One Way Trip Time [Greg_Troxel] [Greg_Troxel]
twcss 3428 tcp 2Wire CSS [Wire_IANA_Contact] [Wire_IANA_Contact] 2002-02
twcss 3428 udp 2Wire CSS [Wire_IANA_Contact] [Wire_IANA_Contact] 2002-02
omviserver 4428 tcp OMV-Investigation Server-Client [Serge_Vacquier] [Serge_Vacquier] 2009-05-20
4428 udp Reserved
telaconsole 5428 tcp TELACONSOLE [Joseph_M_Newcomer] [Joseph_M_Newcomer]
telaconsole 5428 udp TELACONSOLE [Joseph_M_Newcomer] [Joseph_M_Newcomer]
ovladmgr 7428 tcp OpenView DM Log Agent Manager [Dave_Lamb] [Dave_Lamb]
ovladmgr 7428 udp OpenView DM Log Agent Manager [Dave_Lamb] [Dave_Lamb]

Contact Information

ID Name Contact URI Last Updated
[Dave_Lamb] Dave Lamb mailto:rdl&rdl.cnd.hp.com
[Greg_Troxel] Greg Troxel mailto:gdt&ir.bbn.com
[Harald_Schlangmann] Harald Schlangmann mailto:schlangm&informatik.uni-muenchen.de
[Joseph_M_Newcomer] Joseph M. Newcomer mailto:newcomer&flounder.com
[Serge_Vacquier] Serge Vacquier mailto:svacquier&axway.com 2019-03-29
[Wire_IANA_Contact] 2Wire IANA Contact mailto:iana&2wire.com 2002-04