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
rtsserv 2500 tcp Resource Tracking system server
rtsserv 2500 udp Resource Tracking system server
icl-twobase1 25000 tcp icl-twobase1 [J_A_Sever] [J_A_Sever]
icl-twobase1 25000 udp icl-twobase1 [J_A_Sever] [J_A_Sever]
icl-twobase2 25001 tcp icl-twobase2 [J_A_Sever] [J_A_Sever]
icl-twobase2 25001 udp icl-twobase2 [J_A_Sever] [J_A_Sever]
icl-twobase3 25002 tcp icl-twobase3 [J_A_Sever] [J_A_Sever]
icl-twobase3 25002 udp icl-twobase3 [J_A_Sever] [J_A_Sever]
icl-twobase4 25003 tcp icl-twobase4 [J_A_Sever] [J_A_Sever]
icl-twobase4 25003 udp icl-twobase4 [J_A_Sever] [J_A_Sever]
icl-twobase5 25004 tcp icl-twobase5 [J_A_Sever] [J_A_Sever]
icl-twobase5 25004 udp icl-twobase5 [J_A_Sever] [J_A_Sever]
icl-twobase6 25005 tcp icl-twobase6 [J_A_Sever] [J_A_Sever]
icl-twobase6 25005 udp icl-twobase6 [J_A_Sever] [J_A_Sever]
icl-twobase7 25006 tcp icl-twobase7 [J_A_Sever] [J_A_Sever]
icl-twobase7 25006 udp icl-twobase7 [J_A_Sever] [J_A_Sever]
icl-twobase8 25007 tcp icl-twobase8 [J_A_Sever] [J_A_Sever]
icl-twobase8 25007 udp icl-twobase8 [J_A_Sever] [J_A_Sever]
icl-twobase9 25008 tcp icl-twobase9 [J_A_Sever] [J_A_Sever]
icl-twobase9 25008 udp icl-twobase9 [J_A_Sever] [J_A_Sever]
icl-twobase10 25009 tcp icl-twobase10 [J_A_Sever] [J_A_Sever]
icl-twobase10 25009 udp icl-twobase10 [J_A_Sever] [J_A_Sever]

Contact Information

ID Name Contact URI Last Updated
[J_A_Sever] J. A. (Tony) Sever mailto:J.A.Sever&bra0119.wins.icl.co.uk