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]

Available Formats

CSV

XML

HTML

Plain text
Service Name Port Number Transport Protocol Description Assignee Contact Registration Date Modification Date Reference Service Code Unauthorized Use Reported Assignment Notes
ariel2 421 tcp Ariel 2
ariel2 421 udp Ariel 2
gandalf-lm 1421 tcp Gandalf License Manager [gilmer] [gilmer]
gandalf-lm 1421 udp Gandalf License Manager [gilmer] [gilmer]
g-talk 2421 tcp G-Talk [Matt_Hammond] [Matt_Hammond]
g-talk 2421 udp G-Talk [Matt_Hammond] [Matt_Hammond]
bmap 3421 tcp Bull Apprise portmapper [Jeremy_Gilbert] [Jeremy_Gilbert]
bmap 3421 udp Bull Apprise portmapper [Jeremy_Gilbert] [Jeremy_Gilbert]
scaleft 4421 tcp Multi-Platform Remote Management for Cloud Infrastructure [ScaleFT_Inc] [Paul_Querna] 2016-04-07
4421 udp Reserved
netsupport2 5421 tcp Net Support 2 [Paul_Sanders] [Paul_Sanders]
netsupport2 5421 udp Net Support 2 [Paul_Sanders] [Paul_Sanders]
nim-wan 6421 tcp NIM_WAN [Rik_Ditter] [Rik_Ditter] 2006-02
nim-wan 6421 udp NIM_WAN [Rik_Ditter] [Rik_Ditter] 2006-02
mtportmon 7421 tcp Matisse Port Monitor [Didier_Cabannes] [Didier_Cabannes] 2004-11
mtportmon 7421 udp Matisse Port Monitor [Didier_Cabannes] [Didier_Cabannes] 2004-11
36413-36421 Unassigned
38413-38421 Unassigned

Contact Information

ID Name Contact URI Last Updated
[Didier_Cabannes] Didier Cabannes mailto:Didier&matisse.com 2004-11
[Jeremy_Gilbert] Jeremy Gilbert mailto:J.Gilbert&ma30.bull.com
[Matt_Hammond] Matt Hammond mailto:matt_hammond&four-sight.co.uk
[Paul_Querna] Paul Querna mailto:paul.querna&scaleft.com 2016-04-07
[Paul_Sanders] Paul Sanders mailto:p.sanders&dial.pipex.com
[Rik_Ditter] Rik Ditter mailto:managers&generationtechnologies.com 2006-02
[ScaleFT_Inc] ScaleFT, Inc mailto:notices&scaleft.com 2016-04-07
[gilmer] mailto:gilmer&gandalf.ca