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
2200 tcp Reserved This entry has been removed on 2019-07-05.
2200 udp Reserved This entry has been removed on 2019-07-05.
snapenetio 22000 tcp SNAPenetIO [Kevin_Kuhns] [Kevin_Kuhns]
snapenetio 22000 udp SNAPenetIO [Kevin_Kuhns] [Kevin_Kuhns]
optocontrol 22001 tcp OptoControl [Kevin_Kuhns] [Kevin_Kuhns]
optocontrol 22001 udp OptoControl [Kevin_Kuhns] [Kevin_Kuhns]
optohost002 22002 tcp Opto Host Port 2 [Doug_Leany] [Doug_Leany] 2006-09
optohost002 22002 udp Opto Host Port 2 [Doug_Leany] [Doug_Leany] 2006-09
optohost003 22003 tcp Opto Host Port 3 [Doug_Leany] [Doug_Leany] 2006-09
optohost003 22003 udp Opto Host Port 3 [Doug_Leany] [Doug_Leany] 2006-09
optohost004 22004 tcp Opto Host Port 4 [Doug_Leany] [Doug_Leany] 2006-09
optohost004 22004 udp Opto Host Port 4 [Doug_Leany] [Doug_Leany] 2006-09
optohost004 22005 tcp Opto Host Port 5 [Doug_Leany] [Doug_Leany] 2006-09
optohost004 22005 udp Opto Host Port 5 [Doug_Leany] [Doug_Leany] 2006-09
22006-22124 Unassigned

Contact Information

ID Name Contact URI Last Updated
[Doug_Leany] Doug Leany mailto:DLEANY&opto22.com 2006-09
[Kevin_Kuhns] Kevin Kuhns mailto:kkuhns&opto22.com