Service Name and Transport Protocol Port Number Registry

Last Updated
2026-03-27
Expert(s)
TCP/UDP: Joe Touch; Eliot Lear, Kumiko Ono, Wes Eddy, Brian Trammell, 
Jana Iyengar, 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>
51 Reserved 2013-05-24 This entry is being removed on 2013-05-24.
bootps 67 tcp Bootstrap Protocol Server [Bill_Croft] [Bill_Croft] [RFC951] Defined TXT keys: None
imap 143 tcp Internet Message Access Protocol [IESG] [IETF_Chair] 2021-02-22 [RFC3501][RFC9051]
143 udp Reserved 2021-02-22 [RFC9051]
aed-512 149 tcp AED 512 Emulation Service [Albert_G_Broscius] [Albert_G_Broscius]
aed-512 149 udp AED 512 Emulation Service [Albert_G_Broscius] [Albert_G_Broscius]
hems 151 tcp HEMS
hems 151 udp HEMS
matip-type-a 350 tcp MATIP Type A [Alain_Robert] [Alain_Robert] [RFC2351]
matip-type-a 350 udp MATIP Type A [Alain_Robert] [Alain_Robert] [RFC2351]
matip-type-b 351 tcp MATIP Type B [Alain_Robert] [Alain_Robert] [RFC2351]
matip-type-b 351 udp MATIP Type B [Alain_Robert] [Alain_Robert] [RFC2351]
bhoetty 351 tcp bhoetty [John_Kelly] [John_Kelly] This entry records an unassigned but widespread use (added 5/21/97)
bhoetty 351 udp bhoetty [John_Kelly] [John_Kelly] This entry records an unassigned but widespread use (added 5/21/97)
sfs-smp-net 451 tcp Cray Network Semaphore server
sfs-smp-net 451 udp Cray Network Semaphore server
fcp 510 tcp FirstClass Protocol [Mike_Marshburn] [Mike_Marshburn]
fcp 510 udp FirstClass Protocol [Mike_Marshburn] [Mike_Marshburn]
passgo 511 tcp PassGo [John_Rainford] [John_Rainford]
passgo 511 udp PassGo [John_Rainford] [John_Rainford]
exec 512 tcp remote process execution; authentication performed using passwords and UNIX login names
comsat 512 udp
biff 512 udp used by mail system to notify users of new mail received; currently receives messages only from processes on the same machine
login 513 tcp remote login a la telnet; automatic authentication performed based on priviledged port numbers and distributed data bases which identify "authentication domains"
who 513 udp maintains data bases showing who's logged in to machines on a local net and the load average of the machine
shell 514 tcp cmd like exec, but automatic authentication is performed as for login server
syslog 514 udp 2020-06-01 [RFC5426]
printer 515 tcp spooler
printer 515 udp spooler
videotex 516 tcp videotex [Daniel_Mavrakis] [Daniel_Mavrakis]
videotex 516 udp videotex [Daniel_Mavrakis] [Daniel_Mavrakis]
talk 517 tcp like tenex link, but across machine - unfortunately, doesn't use link protocol (this is actually just a rendezvous port from which a tcp connection is established)
talk 517 udp like tenex link, but across machine - unfortunately, doesn't use link protocol (this is actually just a rendezvous port from which a tcp connection is established)
ntalk 518 tcp
ntalk 518 udp
utime 519 tcp unixtime
utime 519 udp unixtime
cybercash 551 tcp cybercash [Donald_E_Eastlake] [Donald_E_Eastlake] [RFC1898]
cybercash 551 udp cybercash [Donald_E_Eastlake] [Donald_E_Eastlake] [RFC1898]
ieee-mms 651 tcp IEEE MMS [Curtis_Anderson] [Curtis_Anderson]
ieee-mms 651 udp IEEE MMS [Curtis_Anderson] [Curtis_Anderson]
pana 716 udp PANA Messages [RFC5191]
pump 751 tcp
pump 751 udp
imaps 993 tcp IMAP over TLS protocol [IESG] [IETF_Chair] 2021-02-22 [RFC3501][RFC8314][RFC9051]
993 udp Reserved 2021-02-22 [RFC9051]
6a44 1027 udp IPv6 Behind NAT44 CPEs [IESG] [IETF_Chair] 2012-08-02 [RFC6751]
optima-vnet 1051 tcp Optima VNET [Ralf_Doewich] [Ralf_Doewich]
optima-vnet 1051 udp Optima VNET [Ralf_Doewich] [Ralf_Doewich]
unizensus 1151 tcp Unizensus Login Server [Dirk_Materlik] [Dirk_Materlik] 2005-11
unizensus 1151 udp Unizensus Login Server [Dirk_Materlik] [Dirk_Materlik] 2005-11
servergraph 1251 tcp servergraph [Lindsay_Morris] [Lindsay_Morris]
servergraph 1251 udp servergraph [Lindsay_Morris] [Lindsay_Morris]
equationbuilder 1351 tcp Digital Tool Works (MIT) [Terrence_J_Talbot] [Terrence_J_Talbot]
equationbuilder 1351 udp Digital Tool Works (MIT) [Terrence_J_Talbot] [Terrence_J_Talbot]
infoman 1451 tcp IBM Information Management [Karen_Burns] [Karen_Burns]
infoman 1451 udp IBM Information Management [Karen_Burns] [Karen_Burns]
mvx-lm 1510 tcp Midland Valley Exploration Ltd. Lic. Man. [Neil_Salter] [Neil_Salter]
mvx-lm 1510 udp Midland Valley Exploration Ltd. Lic. Man. [Neil_Salter] [Neil_Salter]
3l-l1 1511 tcp 3l-l1 [Ian_A_Young] [Ian_A_Young]
3l-l1 1511 udp 3l-l1 [Ian_A_Young] [Ian_A_Young]
wins 1512 tcp Microsoft's Windows Internet Name Service [Pradeep_Bahl] [Pradeep_Bahl]
wins 1512 udp Microsoft's Windows Internet Name Service [Pradeep_Bahl] [Pradeep_Bahl]
fujitsu-dtc 1513 tcp Fujitsu Systems Business of America, Inc
fujitsu-dtc 1513 udp Fujitsu Systems Business of America, Inc
fujitsu-dtcns 1514 tcp Fujitsu Systems Business of America, Inc [Charles_A_Higgins] [Charles_A_Higgins]
fujitsu-dtcns 1514 udp Fujitsu Systems Business of America, Inc [Charles_A_Higgins] [Charles_A_Higgins]
ifor-protocol 1515 tcp ifor-protocol [Dr_R_P_Alston] [Dr_R_P_Alston]
ifor-protocol 1515 udp ifor-protocol [Dr_R_P_Alston] [Dr_R_P_Alston]
vpad 1516 tcp Virtual Places Audio data
vpad 1516 udp Virtual Places Audio data
vpac 1517 tcp Virtual Places Audio control
vpac 1517 udp Virtual Places Audio control
vpvd 1518 tcp Virtual Places Video data
vpvd 1518 udp Virtual Places Video data
vpvc 1519 tcp Virtual Places Video control [Avshalom_Houri] [Avshalom_Houri]
vpvc 1519 udp Virtual Places Video control [Avshalom_Houri] [Avshalom_Houri]
hecmtl-db 1551 tcp HECMTL-DB [Maxime_Belanger] [Maxime_Belanger]
hecmtl-db 1551 udp HECMTL-DB [Maxime_Belanger] [Maxime_Belanger]
shiva-confsrvr 1651 tcp shiva_confsrvr

IANA assigned this well-formed service name as a replacement for "shiva_confsrvr".
[Mike_Horowitz] [Mike_Horowitz]
shiva_confsrvr 1651 tcp shiva_confsrvr [Mike_Horowitz] [Mike_Horowitz] This entry is an alias to "shiva-confsrvr". This entry is now historic, not usable for use with many common service discovery mechanisms.
shiva-confsrvr 1651 udp shiva_confsrvr

IANA assigned this well-formed service name as a replacement for "shiva_confsrvr".
[Mike_Horowitz] [Mike_Horowitz]
shiva_confsrvr 1651 udp shiva_confsrvr [Mike_Horowitz] [Mike_Horowitz] This entry is an alias to "shiva-confsrvr". This entry is now historic, not usable for use with many common service discovery mechanisms.
swiftnet 1751 tcp SwiftNet [Terry_Lim] [Terry_Lim]
swiftnet 1751 udp SwiftNet [Terry_Lim] [Terry_Lim]
ctcd 1851 tcp ctcd [John_Ryan] [John_Ryan]
ctcd 1851 udp ctcd [John_Ryan] [John_Ryan]
bcs-lmserver 1951 tcp bcs-lmserver [Andy_Warner] [Andy_Warner]
bcs-lmserver 1951 udp bcs-lmserver [Andy_Warner] [Andy_Warner]
epnsdp 2051 tcp EPNSDP [Hiroyasu_Ogata] [Hiroyasu_Ogata]
epnsdp 2051 udp EPNSDP [Hiroyasu_Ogata] [Hiroyasu_Ogata]
docent 2151 tcp DOCENT [Hali_Lindbloom] [Hali_Lindbloom]
docent 2151 udp DOCENT [Hali_Lindbloom] [Hali_Lindbloom]
dif-port 2251 tcp Distributed Framework Port [Sebastien_Lambla] [Sebastien_Lambla]
dif-port 2251 udp Distributed Framework Port [Sebastien_Lambla] [Sebastien_Lambla]
psrserver 2351 tcp psrserver
psrserver 2351 udp psrserver
netchat 2451 tcp netchat [Julian_Mehnle] [Julian_Mehnle]

Contact Information

ID Name Organization Contact URI Last Updated
[Alain_Robert] Alain Robert mailto:arobert&par.sita.int
[Albert_G_Broscius] Albert G. Broscius mailto:broscius&dsl.cis.upenn.edu
[Andy_Warner] Andy Warner mailto:andyw&knoware.nl
[Avshalom_Houri] Avshalom Houri mailto:Avshalom&ubique.com
[Bill_Croft] Bill Croft mailto:Croft&sumex-aim.stanford.edu
[Charles_A_Higgins] Charles A. Higgins mailto:75730.2257&compuserve.com
[Curtis_Anderson] Curtis Anderson mailto:canderson&turbolinux.com
[Daniel_Mavrakis] Daniel Mavrakis mailto:system&venus.mctel.fr
[Dirk_Materlik] Dirk Materlik mailto:materlik&blubbsoft.de 2005-11
[Donald_E_Eastlake] Donald E. Eastlake 3rd mailto:d3e3e3&gmail.com
[Dr_R_P_Alston] Dr. R.P. Alston mailto:robin&gradient.com
[Hali_Lindbloom] Hali Lindbloom mailto:halil&docent.com
[Hiroyasu_Ogata] Hiroyasu Ogata mailto:Ogata.Hiroyasu&exc.epson.co.jp
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Ian_A_Young] Ian A. Young mailto:iay&threel.co.uk
[John_Kelly] John Kelly mailto:johnk&bellhow.com
[John_Rainford] John Rainford mailto:jrainford&passgo.com
[John_Ryan] John Ryan mailto:john&cybertrace.com
[Julian_Mehnle] Julian Mehnle mailto:julian&mehnle.net
[Karen_Burns] Karen Burns
[Lindsay_Morris] Lindsay Morris mailto:lmorris&servergraph.com
[Maxime_Belanger] Maxime Belanger mailto:R173&hec.ca
[Mike_Horowitz] Mike Horowitz mailto:mah&shiva.com
[Mike_Marshburn] Mike Marshburn mailto:paul&softarc.com
[Neil_Salter] Neil Salter mailto:neil&indigo2.mvel.demon.co.uk
[Pradeep_Bahl] Pradeep Bahl mailto:pradeepb&microsoft.com
[Ralf_Doewich] Ralf Doewich mailto:ralf.doewich&optimatele.com
[Sebastien_Lambla] Sebastien Lambla mailto:lambla&bouygtel.com
[Terrence_J_Talbot] Terrence J. Talbot mailto:lexcube!tjt&bu.edu
[Terry_Lim] Terry Lim mailto:tkl&pentek.com