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
escp-ip 621 tcp ESCP [Lai_Zit_Seng] [Lai_Zit_Seng]
escp-ip 621 udp ESCP [Lai_Zit_Seng] [Lai_Zit_Seng]
softdataphone 1621 tcp softdataphone [Dror_Gill] [Dror_Gill]
softdataphone 1621 udp softdataphone [Dror_Gill] [Dror_Gill]
miles-apart 2621 tcp Miles Apart Jukebox Server [Michael_Rathmann] [Michael_Rathmann]
miles-apart 2621 udp Miles Apart Jukebox Server [Michael_Rathmann] [Michael_Rathmann]
ep-nsp 3621 tcp EPSON Network Screen Port [SEIKO_EPSON_3] [SEIKO_EPSON_3] 2002-10
ep-nsp 3621 udp EPSON Network Screen Port [SEIKO_EPSON_3] [SEIKO_EPSON_3] 2002-10
4621 tcp Reserved
ventoso 4621 udp Bidirectional single port remote radio VOIP and Control stream [Ventoso_Integrated_Peripherals] [John_Lindsey] 2016-03-04
6210-6221 Unassigned
kftp 6621 tcp Kerberos V5 FTP Control [Robert_J_Scott] [Robert_J_Scott] 2005-08
kftp 6621 udp Kerberos V5 FTP Control [Robert_J_Scott] [Robert_J_Scott] 2005-08
31621-31684 Unassigned

Contact Information

ID Name Organization Contact URI Last Updated
[Dror_Gill] Dror Gill mailto:drorgi&vnet.ibm.com
[John_Lindsey] John Lindsey mailto:john.lindsey&nilesradio.com 2016-03-04
[Lai_Zit_Seng] Lai Zit Seng mailto:lzs&pobox.com
[Michael_Rathmann] Michael Rathmann mailto:rathmann_ia&milesinfo.com
[Robert_J_Scott] Robert J. Scott mailto:rob&hpcmo.hpc.mil 2005-08
[SEIKO_EPSON_3] SEIKO EPSON mailto:Sato.Minoru3&exc.epson.co.jp 2002-10
[Ventoso_Integrated_Peripherals] Ventoso Integrated Peripherals mailto:john.lindsey&nilesradio.com 2016-03-04