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
mdc-portmapper 685 tcp MDC Port Mapper [Noah_Paul] [Noah_Paul]
mdc-portmapper 685 udp MDC Port Mapper [Noah_Paul] [Noah_Paul]
n2nremote 1685 tcp n2nremote [Kin_Chan_2] [Kin_Chan_2]
n2nremote 1685 udp n2nremote [Kin_Chan_2] [Kin_Chan_2]
mpnjsocl 2685 tcp mpnjsocl
mpnjsocl 2685 udp mpnjsocl
dsx-agent 3685 tcp DS Expert Agent [Jason_Lockett][Melanie_Kacerek] [Jason_Lockett][Melanie_Kacerek] 2008-12-16
dsx-agent 3685 udp DS Expert Agent [Jason_Lockett][Melanie_Kacerek] [Jason_Lockett][Melanie_Kacerek] 2008-12-16
dtn-bundle 4556 dccp DTN Bundle DCCP CL Protocol 2013-11-12 2014-02-21 [RFC7122] 1685351985
autopac 4685 tcp Autopac Protocol [Peter_Hallenbeck] [Peter_Hallenbeck] 2005-08
autopac 4685 udp Autopac Protocol [Peter_Hallenbeck] [Peter_Hallenbeck] 2005-08
5685-5686 Unassigned
iccrushmore 6850 tcp ICCRUSHMORE [Dave_Hubbard] [Dave_Hubbard]
iccrushmore 6850 udp ICCRUSHMORE [Dave_Hubbard] [Dave_Hubbard]
6851-6867 Unassigned
8676-8685 Unassigned
dsx-monitor 31685 tcp DS Expert Monitor

IANA assigned this well-formed service name as a replacement for "dsx_monitor".
[John_Lowery] [John_Lowery] 2008-08-21
dsx_monitor 31685 tcp DS Expert Monitor [John_Lowery] [John_Lowery] 2008-08-21 This entry is an alias to "dsx-monitor". This entry is now historic, not usable for use with many common service discovery mechanisms.
31685 udp Reserved

Contact Information

ID Name Organization Contact URI Last Updated
[Dave_Hubbard] Dave Hubbard mailto:dave&icc.net
[Jason_Lockett] Jason Lockett mailto:Jay.Lockett&quest.com 2008-12-16
[John_Lowery] John Lowery NetPro Computing mailto:jlowery&netpro.com 2008-08-21
[Kin_Chan_2] Kin Chan mailto:kchan&net2net.com
[Melanie_Kacerek] Melanie Kacerek mailto:melanie.kacerek&quest.com 2008-12-16
[Noah_Paul] Noah Paul mailto:noahp&altavista.net
[Peter_Hallenbeck] Peter Hallenbeck mailto:pete&consumertechnologiesgroup.com 2005-08