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
msexch-routing 691 tcp MS Exchange Routing [David_Lemson] [David_Lemson]
msexch-routing 691 udp MS Exchange Routing [David_Lemson] [David_Lemson]
empire-empuma 1691 tcp empire-empuma [Bobby_Krupczak] [Bobby_Krupczak]
empire-empuma 1691 udp empire-empuma [Bobby_Krupczak] [Bobby_Krupczak]
itinternet 2691 tcp ITInternet ISM Server [Ron_Ehli] [Ron_Ehli]
itinternet 2691 udp ITInternet ISM Server [Ron_Ehli] [Ron_Ehli]
magaya-network 3691 tcp Magaya Network Port [Jesus_David_Rodrigue] [Jesus_David_Rodrigue] 2003-02
magaya-network 3691 udp Magaya Network Port [Jesus_David_Rodrigue] [Jesus_David_Rodrigue] 2003-02
mtn 4691 tcp monotone Netsync Protocol [Thomas_Keller] [Thomas_Keller] 2010-12-22
mtn 4691 udp monotone Netsync Protocol [Thomas_Keller] [Thomas_Keller] 2010-12-22
6691-6695 Unassigned
7691-7696 Unassigned

Contact Information

ID Name Contact URI Last Updated
[Bobby_Krupczak] Bobby Krupczak mailto:rdk&empiretech.com
[David_Lemson] David Lemson mailto:dlemson&microsoft.com
[Jesus_David_Rodrigue] Jesus David Rodriguez mailto:jesusdavid&magaya.com 2003-02
[Ron_Ehli] Ron Ehli mailto:ron&itinternet.net
[Thomas_Keller] Thomas Keller mailto:me&thomaskeller.biz 2010-12-22