Service Name and Transport Protocol Port Number Registry

Last Updated
2026-09-01
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
etftp 1818 tcp Enhanced Trivial File Transfer Protocol [William_Polites] [William_Polites]
etftp 1818 udp Enhanced Trivial File Transfer Protocol [William_Polites] [William_Polites]
18137-18180 Unassigned
opsec-cvp 18181 tcp OPSEC CVP [Alon_Kantor] [Alon_Kantor]
opsec-cvp 18181 udp OPSEC CVP [Alon_Kantor] [Alon_Kantor]
opsec-ufp 18182 tcp OPSEC UFP [Alon_Kantor] [Alon_Kantor]
opsec-ufp 18182 udp OPSEC UFP [Alon_Kantor] [Alon_Kantor]
opsec-sam 18183 tcp OPSEC SAM [Alon_Kantor] [Alon_Kantor]
opsec-sam 18183 udp OPSEC SAM [Alon_Kantor] [Alon_Kantor]
opsec-lea 18184 tcp OPSEC LEA [Alon_Kantor] [Alon_Kantor]
opsec-lea 18184 udp OPSEC LEA [Alon_Kantor] [Alon_Kantor]
opsec-omi 18185 tcp OPSEC OMI [Alon_Kantor] [Alon_Kantor]
opsec-omi 18185 udp OPSEC OMI [Alon_Kantor] [Alon_Kantor]
ohsc 18186 tcp Occupational Health SC [David_Fudge] [David_Fudge] 2003-08
ohsc 18186 udp Occupational Health Sc [David_Fudge] [David_Fudge] 2003-08
opsec-ela 18187 tcp OPSEC ELA [Alon_Kantor] [Alon_Kantor]
opsec-ela 18187 udp OPSEC ELA [Alon_Kantor] [Alon_Kantor]
18188-18240 Unassigned

Contact Information

ID Name Contact URI Last Updated
[Alon_Kantor] Alon Kantor mailto:alonk&checkpoint.com
[David_Fudge] David Fudge mailto:david.fudge&tssi.co.uk 2003-08
[William_Polites] William Polites mailto:wpolites&mitre.org