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
ssh 22 tcp The Secure Shell (SSH) Protocol [RFC4251] Defined TXT keys: u=<username> p=<password>
ssh 22 udp The Secure Shell (SSH) Protocol [RFC4251] Defined TXT keys: u=<username> p=<password>
name 42 tcp Host Name Server
name 42 udp Host Name Server
nameserver 42 tcp Host Name Server
nameserver 42 udp Host Name Server
bl-idm 142 tcp Britton-Lee IDM [Susie_Snitzer] [Susie_Snitzer]
bl-idm 142 udp Britton-Lee IDM [Susie_Snitzer] [Susie_Snitzer]
direct 242 tcp Direct [Herb_Sutter] [Paul_Horton]
direct 242 udp Direct [Herb_Sutter] [Paul_Horton]
smpte 420 tcp SMPTE [Si_Becker] [Si_Becker]
smpte 420 udp SMPTE [Si_Becker] [Si_Becker]
ariel2 421 tcp Ariel 2
ariel2 421 udp Ariel 2
ariel3 422 tcp Ariel 3 [Joel_Karafin] [Joel_Karafin]
ariel3 422 udp Ariel 3 [Joel_Karafin] [Joel_Karafin]
opc-job-start 423 tcp IBM Operations Planning and Control Start
opc-job-start 423 udp IBM Operations Planning and Control Start
opc-job-track 424 tcp IBM Operations Planning and Control Track [Conny_Larsson] [Conny_Larsson]
opc-job-track 424 udp IBM Operations Planning and Control Track [Conny_Larsson] [Conny_Larsson]
icad-el 425 tcp ICAD [Larry_Stone] [Larry_Stone]
icad-el 425 udp ICAD [Larry_Stone] [Larry_Stone]
smartsdp 426 tcp smartsdp [Marie_Pierre_Belange] [Marie_Pierre_Belange]
smartsdp 426 udp smartsdp [Marie_Pierre_Belange] [Marie_Pierre_Belange]
svrloc 427 tcp Server Location [Veizades] [Veizades]
svrloc 427 udp Server Location [Veizades] [Veizades]
ocs-cmu 428 tcp OCS_CMU

IANA assigned this well-formed service name as a replacement for "ocs_cmu".
ocs_cmu 428 tcp OCS_CMU This entry is an alias to "ocs-cmu". This entry is now historic, not usable for use with many common service discovery mechanisms.
ocs-cmu 428 udp OCS_CMU

IANA assigned this well-formed service name as a replacement for "ocs_cmu".
ocs_cmu 428 udp OCS_CMU This entry is an alias to "ocs-cmu". This entry is now historic, not usable for use with many common service discovery mechanisms.
ocs-amu 429 tcp OCS_AMU

IANA assigned this well-formed service name as a replacement for "ocs_amu".
[Florence_Wyman] [Florence_Wyman]
ocs_amu 429 tcp OCS_AMU [Florence_Wyman] [Florence_Wyman] This entry is an alias to "ocs-amu". This entry is now historic, not usable for use with many common service discovery mechanisms.
ocs-amu 429 udp OCS_AMU

IANA assigned this well-formed service name as a replacement for "ocs_amu".
[Florence_Wyman] [Florence_Wyman]
ocs_amu 429 udp OCS_AMU [Florence_Wyman] [Florence_Wyman] This entry is an alias to "ocs-amu". This entry is now historic, not usable for use with many common service discovery mechanisms.
cvc-hostd 442 tcp cvc_hostd

IANA assigned this well-formed service name as a replacement for "cvc_hostd".
[Bill_Davidson] [Bill_Davidson]
cvc_hostd 442 tcp cvc_hostd [Bill_Davidson] [Bill_Davidson] This entry is an alias to "cvc-hostd". This entry is now historic, not usable for use with many common service discovery mechanisms.
cvc-hostd 442 udp cvc_hostd

IANA assigned this well-formed service name as a replacement for "cvc_hostd".
[Bill_Davidson] [Bill_Davidson]
cvc_hostd 442 udp cvc_hostd [Bill_Davidson] [Bill_Davidson] This entry is an alias to "cvc-hostd". This entry is now historic, not usable for use with many common service discovery mechanisms.
syslog 514 udp 2020-06-01 [RFC5426]
commerce 542 tcp commerce [Randy_Epstein] [Randy_Epstein]
commerce 542 udp commerce [Randy_Epstein] [Randy_Epstein]
nntps 563 tcp nntp protocol over TLS/SSL (was snntp) [IESG] [IETF_Chair] 2018-07-06 [RFC4642]
nntps 563 udp nntp protocol over TLS/SSL (was snntp) [IESG] [IETF_Chair] 2018-07-06 [RFC4642]
soap-beep 605 tcp SOAP over BEEP [RFC4227]
soap-beep 605 udp SOAP over BEEP [RFC4227]
esro-emsdp 642 tcp ESRO-EMSDP V1.3 [Mohsen_Banan_2] [Mohsen_Banan_2]
esro-emsdp 642 udp ESRO-EMSDP V1.3 [Mohsen_Banan_2] [Mohsen_Banan_2]
lmp 701 tcp Link Management Protocol (LMP) [RFC4204]
lmp 701 udp Link Management Protocol (LMP) [RFC4204]
netrcs 742 tcp Network based Rev. Cont. Sys. [Gordon_C_Galligher] [Gordon_C_Galligher]
netrcs 742 udp Network based Rev. Cont. Sys. [Gordon_C_Galligher] [Gordon_C_Galligher]
netconf-ssh 830 tcp NETCONF over SSH [RFC6242]
netconf-ssh 830 udp NETCONF over SSH [RFC6242]
afrog 1042 tcp Subnet Roaming [Michael_Chapman] [Michael_Chapman] 2004-11
afrog 1042 udp Subnet Roaming [Michael_Chapman] [Michael_Chapman] 2004-11
edtools 1142 tcp User Discovery Service [Lee_Dolson] [Lee_Dolson] 2006-01
edtools 1142 udp User Discovery Service [Lee_Dolson] [Lee_Dolson] 2006-01
c1222-acse 1153 tcp ANSI C12.22 Port [RFC6142]
c1222-acse 1153 udp ANSI C12.22 Port [RFC6142]
nmasoverip 1242 tcp NMAS over IP [Hal_Henderson] [Hal_Henderson]
nmasoverip 1242 udp NMAS over IP [Hal_Henderson] [Hal_Henderson]
esbroker 1342 tcp ESBroker [Alexander_Medvinsky] [Alexander_Medvinsky]
esbroker 1342 udp ESBroker [Alexander_Medvinsky] [Alexander_Medvinsky]
timbuktu-srv4 1420 tcp Timbuktu Service 4 Port [Marc_Epard] [Marc_Epard]
timbuktu-srv4 1420 udp Timbuktu Service 4 Port [Marc_Epard] [Marc_Epard]
gandalf-lm 1421 tcp Gandalf License Manager [gilmer] [gilmer]
gandalf-lm 1421 udp Gandalf License Manager [gilmer] [gilmer]
autodesk-lm 1422 tcp Autodesk License Manager [David_Ko] [David_Ko]
autodesk-lm 1422 udp Autodesk License Manager [David_Ko] [David_Ko]
essbase 1423 tcp Essbase Arbor Software
essbase 1423 udp Essbase Arbor Software
hybrid 1424 tcp Hybrid Encryption Protocol [Howard_Hart] [Howard_Hart]
hybrid 1424 udp Hybrid Encryption Protocol [Howard_Hart] [Howard_Hart]
zion-lm 1425 tcp Zion Software License Manager [David_Ferrero] [David_Ferrero]
zion-lm 1425 udp Zion Software License Manager [David_Ferrero] [David_Ferrero]
sais 1426 tcp Satellite-data Acquisition System 1 [Bill_Taylor] [Bill_Taylor]
sais 1426 udp Satellite-data Acquisition System 1 [Bill_Taylor] [Bill_Taylor]
mloadd 1427 tcp mloadd monitoring tool [Bob_Braden_2] [Bob_Braden_2]
mloadd 1427 udp mloadd monitoring tool [Bob_Braden_2] [Bob_Braden_2]
informatik-lm 1428 tcp Informatik License Manager [Harald_Schlangmann] [Harald_Schlangmann]
informatik-lm 1428 udp Informatik License Manager [Harald_Schlangmann] [Harald_Schlangmann]
nms 1429 tcp Hypercom NMS
nms 1429 udp Hypercom NMS
cadis-2 1442 tcp Cadis License Management [Todd_Wichers] [Todd_Wichers]
cadis-2 1442 udp Cadis License Management [Todd_Wichers] [Todd_Wichers]
gridgen-elmd 1542 tcp gridgen-elmd [John_R_Chawner] [John_R_Chawner]
gridgen-elmd 1542 udp gridgen-elmd [John_R_Chawner] [John_R_Chawner]
isis-am 1642 tcp isis-am
isis-am 1642 udp isis-am
3Com-nsd 1742 tcp 3Com-nsd [Nitza_Steinberg] [Nitza_Steinberg]
3Com-nsd 1742 udp 3Com-nsd [Nitza_Steinberg] [Nitza_Steinberg]
netopia-vo4 1842 tcp netopia-vo4
netopia-vo4 1842 udp netopia-vo4
res 1942 tcp Real Enterprise Service [Bob_Janssen] [Bob_Janssen]
res 1942 udp Real Enterprise Service [Bob_Janssen] [Bob_Janssen]
isis 2042 tcp isis
isis 2042 udp isis
tdmoip 2142 tcp TDM OVER IP [Yaakov_Stein] [Yaakov_Stein] 2016-09-21 [RFC5087]
tdmoip 2142 udp TDM OVER IP [Yaakov_Stein] [Yaakov_Stein] 2016-09-21 [RFC5087]
foliocorp 2242 tcp Folio Remote Server [Pat_Mcgowan] [Pat_Mcgowan]

Contact Information

ID Name Organization Contact URI Last Updated
[Alexander_Medvinsky] Alexander Medvinsky mailto:smedvinsky&gi.com
[Bill_Davidson] Bill Davidson mailto:billd&equalizer.cray.com
[Bill_Taylor] Bill Taylor mailto:sais&ssec.wisc.edu
[Bob_Braden_2] Bob Braden mailto:braden&isi.edu
[Bob_Janssen] Bob Janssen mailto:bob&res.nl
[Conny_Larsson] Conny Larsson mailto:cocke&vnet.ibm.com
[David_Ferrero] David Ferrero mailto:david&zion.com
[David_Ko] David Ko mailto:dko&autodesk.com
[Florence_Wyman] Florence Wyman mailto:wyman&peabody.plk.af.mil
[Gordon_C_Galligher] Gordon C. Galligher mailto:gorpong&ping.chi.il.us
[Hal_Henderson] Hal Henderson mailto:hhenders&novell.com
[Harald_Schlangmann] Harald Schlangmann mailto:schlangm&informatik.uni-muenchen.de
[Herb_Sutter] Herb Sutter mailto:HerbS&cntc.com
[Howard_Hart] Howard Hart mailto:hch&hybrid.com
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Joel_Karafin] Joel Karafin mailto:jkarafin&infotrieve.com
[John_R_Chawner] John R. Chawner tel:+1-817-354-1004
[Larry_Stone] Larry Stone mailto:lcs&icad.com
[Lee_Dolson] Lee Dolson mailto:dolson&f-net.co.kr 2006-01
[Marc_Epard] Marc Epard mailto:marc&netopia.com
[Marie_Pierre_Belange] Marie-Pierre Belanger mailto:belanger_marie&emc.com
[Michael_Chapman] Michael Chapman mailto:mchapman&fortresstech.com 2004-11
[Mohsen_Banan_2] Mohsen Banan mailto:mohsen&neda.com
[Nitza_Steinberg] Nitza Steinberg mailto:nitza&isd.3com.com
[Pat_Mcgowan] Pat Mcgowan mailto:pmcgowan&folio.com
[Paul_Horton] Paul Horton mailto:paul.horton&dxstro.com 2016-05-18
[Randy_Epstein] Randy Epstein mailto:randy&epstein.com 2023-10-18
[Si_Becker] Si Becker mailto:71362.22&compuserve.com
[Susie_Snitzer] Susie Snitzer
[Todd_Wichers] Todd Wichers mailto:twichers&csn.org
[Veizades] mailto:veizades&ftp.com
[Yaakov_Stein] Yaakov Stein mailto:yaakovjstein&gmail.com 2022-02-04
[gilmer] mailto:gilmer&gandalf.ca