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
imap 143 tcp Internet Message Access Protocol [IESG] [IETF_Chair] 2021-02-22 [RFC3501][RFC9051]
stmf 501 tcp STMF [Alan_Ungar] [Alan_Ungar]
stmf 501 udp STMF [Alan_Ungar] [Alan_Ungar]
imaps 993 tcp IMAP over TLS protocol [IESG] [IETF_Chair] 2021-02-22 [RFC3501][RFC8314][RFC9051]
saiscm 1501 tcp Satellite-data Acquisition System 3 [Bill_Taylor] [Bill_Taylor]
saiscm 1501 udp Satellite-data Acquisition System 3 [Bill_Taylor] [Bill_Taylor]
rtsclient 2501 tcp Resource Tracking system client [Aubrey_Turner] [Aubrey_Turner]
rtsclient 2501 udp Resource Tracking system client [Aubrey_Turner] [Aubrey_Turner]
isoft-p2p 3501 tcp iSoft-P2P [David_Walling_2] [David_Walling_2]
isoft-p2p 3501 udp iSoft-P2P [David_Walling_2] [David_Walling_2]
4501 Unassigned [IANA] [IANA] De-registered 08 June 2001
telelpathstart 5010 tcp TelepathStart [Helmuth_Breitenfelln] [Helmuth_Breitenfelln]
telelpathstart 5010 udp TelepathStart [Helmuth_Breitenfelln] [Helmuth_Breitenfelln]
telelpathattack 5011 tcp TelepathAttack [Helmuth_Breitenfelln] [Helmuth_Breitenfelln]
telelpathattack 5011 udp TelepathAttack [Helmuth_Breitenfelln] [Helmuth_Breitenfelln]
nsp 5012 tcp NetOnTap Service [Kim_Hancock] [Kim_Hancock] 2007-10-24
nsp 5012 udp NetOnTap Service [Kim_Hancock] [Kim_Hancock] 2007-10-24
fmpro-v6 5013 tcp FileMaker, Inc. - Proprietary transport [Alex_Chen] [Alex_Chen] 2007-08-01
fmpro-v6 5013 udp FileMaker, Inc. - Proprietary transport [Alex_Chen] [Alex_Chen] 2007-08-01
5014 tcp Reserved
onpsocket 5014 udp Overlay Network Protocol [Roger_Matthias] [Roger_Matthias] 2009-08-24
fmwp 5015 tcp FileMaker, Inc. - Web publishing [Alex_Chen] [Alex_Chen] 2009-11-25
5015 udp Reserved
5016-5019 Unassigned
fcp-addr-srvr2 5501 tcp fcp-addr-srvr2 [Ken_Wittmer] [Ken_Wittmer]
fcp-addr-srvr2 5501 udp fcp-addr-srvr2 [Ken_Wittmer] [Ken_Wittmer]
boks-servc 6501 tcp BoKS Servc

IANA assigned this well-formed service name as a replacement for "boks_servc".
[Magnus_Nystrom] [Magnus_Nystrom] Known Unauthorized Use on port 6501
boks_servc 6501 tcp BoKS Servc [Magnus_Nystrom] [Magnus_Nystrom] Known Unauthorized Use on port 6501 This entry is an alias to "boks-servc". This entry is now historic, not usable for use with many common service discovery mechanisms.
boks-servc 6501 udp BoKS Servc

IANA assigned this well-formed service name as a replacement for "boks_servc".
[Magnus_Nystrom] [Magnus_Nystrom]
boks_servc 6501 udp BoKS Servc [Magnus_Nystrom] [Magnus_Nystrom] This entry is an alias to "boks-servc". This entry is now historic, not usable for use with many common service discovery mechanisms.
ovbus 7501 tcp HP OpenView Bus Daemon [David_M_Rhodes] [David_M_Rhodes] Known Unauthorized Use on port 7501
ovbus 7501 udp HP OpenView Bus Daemon [David_M_Rhodes] [David_M_Rhodes] Known Unauthorized Use on port 7501
cmtp-mgt 8501 tcp CYTEL Message Transfer Management
cmtp-av 8501 udp CYTEL Message Transfer Audio and Video [Frank_Jakel] [Frank_Jakel] 2011-04-29
9501-9521 Unassigned
10501-10539 Unassigned
14501-14935 Unassigned
17501-17554 Unassigned
25010-25099 Unassigned

Contact Information

ID Name Organization Contact URI Last Updated
[Alan_Ungar] Alan Ungar mailto:aungar&farradyne.com
[Alex_Chen] Alex Chen mailto:alex_chen&filemaker.com 2009-11-25
[Aubrey_Turner] Aubrey Turner mailto:S95525ta%25etsuacad.bitnet@ETSUADMN.ETSU.EDU
[Bill_Taylor] Bill Taylor mailto:sais&ssec.wisc.edu
[David_M_Rhodes] David M. Rhodes mailto:davidrho&cnd.hp.com
[David_Walling_2] David Walling mailto:dwalling&isoft.com
[Frank_Jakel] Frank Jäkel mailto:Frank.Jaekel&cytel.de 2011-04-29
[Helmuth_Breitenfelln] Helmuth Breitenfellner mailto:hbreitenf&vnet.imb.com
[IANA] IANA mailto:iana&iana.org
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Ken_Wittmer] Ken Wittmer mailto:kenneth.m.wittmer&accenture.com
[Kim_Hancock] Kim Hancock mailto:registry&dragondex.com 2007-10-24
[Magnus_Nystrom] Magnus Nystrom mailto:magnus&dynas.se
[Roger_Matthias] Roger Matthias mailto:rogermatthias&yahoo.co.uk 2009-08-24