Internet Assigned Numbers Authority

Service Name and Transport Protocol Port Number Registry

Last Updated
2025-08-07
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
scohelp 457 udp scohelp [Faith_Zack] [Faith_Zack]
appleqtc 458 udp apple quick time [Murali_Ranganathan] [Murali_Ranganathan]
ampr-rcmd 459 udp ampr-rcmd [Rob_Janssen] [Rob_Janssen]
skronk 460 udp skronk [Henry_Strickland] [Henry_Strickland]
datasurfsrv 461 udp DataRampSrv
datasurfsrvsec 462 udp DataRampSrvSec [Diane_Downie] [Diane_Downie]
alpes 463 udp alpes [Alain_Durand] [Alain_Durand]
kpasswd 464 udp kpasswd [Greg_Hudson_2] [Greg_Hudson_2] 2023-11-17
igmpv3lite 465 udp IGMP over UDP for SSM [Toerless_Eckert] [Toerless_Eckert]
digital-vrc 466 udp digital-vrc [Peter_Higginson] [Peter_Higginson]
mylex-mapd 467 udp mylex-mapd [Gary_Lewis] [Gary_Lewis]
photuris 468 udp proturis [Bill_Simpson_2] [Bill_Simpson_2]
rcp 469 udp Radio Control Protocol [Jim_Jennings] [Jim_Jennings]
scx-proxy 470 udp scx-proxy [Scott_Narveson] [Scott_Narveson]
mondex 471 udp Mondex [Bill_Reding] [Bill_Reding]
ljk-login 472 udp ljk-login [LJK] [LJK]
hybrid-pop 473 udp hybrid-pop [Rami_Rubin] [Rami_Rubin]
tn-tl-w2 474 udp tn-tl-w2 [Ed_Kress] [Ed_Kress]
tcpnethaspsrv 475 udp tcpnethaspsrv [Michael_Zunke] [Michael_Zunke] 2010-07-23
tn-tl-fd1 476 udp tn-tl-fd1 [Ed_Kress] [Ed_Kress]
ss7ns 477 udp ss7ns [Jean_Michel_URSCH] [Jean_Michel_URSCH]
spsc 478 udp spsc [Mike_Rieker] [Mike_Rieker]
iafserver 479 udp iafserver
iafdbase 480 udp iafdbase [Rick_Yazwinski] [Rick_Yazwinski]
ph 481 udp Ph service [Roland_Hedberg] [Roland_Hedberg]
bgs-nsi 482 udp bgs-nsi [Jon_Saperia] [Jon_Saperia]
ulpnet 483 udp ulpnet [Kevin_Mooney] [Kevin_Mooney]
integra-sme 484 udp Integra Software Management Environment [Randall_Dow] [Randall_Dow]
powerburst 485 udp Air Soft Power Burst [gary] [gary]
avian 486 udp avian [Robert_Ullmann_2] [Robert_Ullmann_2]
saft 487 udp saft Simple Asynchronous File Transfer [Ulli_Horlacher] [Ulli_Horlacher]
gss-http 488 udp gss-http [Doug_Rosenthal] [Doug_Rosenthal]
nest-protocol 489 udp nest-protocol [Gilles_Gameiro] [Gilles_Gameiro]
micom-pfs 490 udp micom-pfs [David_Misunas] [David_Misunas]
go-login 491 udp go-login [Troy_Morrison] [Troy_Morrison]
ticf-1 492 udp Transport Independent Convergence for FNA
ticf-2 493 udp Transport Independent Convergence for FNA [Mamoru_Ito] [Mamoru_Ito]
pov-ray 494 udp POV-Ray [POV_Team_Co_ordinato] [POV_Team_Co_ordinato]
intecourier 495 udp intecourier [Steve_Favor] [Steve_Favor]
pim-rp-disc 496 udp PIM-RP-DISC [Dino_Farinacci] [Dino_Farinacci]
retrospect 497 udp Retrospect backup and restore service [Retrospect_Inc] [JG_Heithcock] 2012-02-02
siam 498 udp siam [Philippe_Gilbert] [Philippe_Gilbert]
iso-ill 499 udp ISO ILL Protocol [Mark_H_Needleman] [Mark_H_Needleman]
isakmp 500 udp isakmp [Mark_Schertler] [Mark_Schertler]
stmf 501 udp STMF [Alan_Ungar] [Alan_Ungar]
mbap 502 udp Modbus Application Protocol [modbus.org] [Dennis_Dube] 2014-06-10
intrinsa 503 udp Intrinsa [Robert_Ford] [Robert_Ford]
citadel 504 udp citadel [Art_Cancro] [Art_Cancro]
mailbox-lm 505 udp mailbox-lm [Beverly_Moody] [Beverly_Moody]
ohimsrv 506 udp ohimsrv [Scott_Powell] [Scott_Powell]
crs 507 udp crs [Brad_Wright] [Brad_Wright]
xvttp 508 udp xvttp [Keith_J_Alphonso] [Keith_J_Alphonso]
snare 509 udp snare [Dennis_Batchelder] [Dennis_Batchelder]
fcp 510 udp FirstClass Protocol [Mike_Marshburn] [Mike_Marshburn]
passgo 511 udp PassGo [John_Rainford] [John_Rainford]
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
who 513 udp maintains data bases showing who's logged in to machines on a local net and the load average of the machine
syslog 514 udp 2020-06-01 [RFC5426]
printer 515 udp spooler
videotex 516 udp videotex [Daniel_Mavrakis] [Daniel_Mavrakis]
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 udp
utime 519 udp unixtime
router 520 udp local routing process (on site); uses variant of Xerox NS routing information protocol - RIP
ripng 521 udp ripng [Robert_E_Minnear] [Robert_E_Minnear]
ulp 522 udp ULP [Max_Morris] [Max_Morris]
ibm-db2 523 udp IBM-DB2 [Juliana_Hsu] [Juliana_Hsu]
ncp 524 udp NCP [Don_Provan_2] [Don_Provan_2]
timed 525 udp timeserver
tempo 526 udp newdate
stx 527 udp Stock IXChange [Ferdi_Ladeira] [Ferdi_Ladeira] 2022-01-25
custix 528 udp Customer IXChange [Ferdi_Ladeira] [Ferdi_Ladeira] 2022-01-25
irc-serv 529 udp IRC-SERV [Brian_Tackett] [Brian_Tackett]
courier 530 udp rpc
conference 531 udp chat
netnews 532 udp readnews
netwall 533 udp for emergency broadcasts [Andreas_Heidemann] [Andreas_Heidemann]
windream 534 udp windream Admin [Uwe_Honermann] [Uwe_Honermann]
iiop 535 udp iiop [Jeff_M_Michaud] [Jeff_M_Michaud]
opalis-rdv 536 udp opalis-rdv [Laurent_Domenech] [Laurent_Domenech]
nmsp 537 udp Networked Media Streaming Protocol [Paul_Santinelli_Jr] [Paul_Santinelli_Jr]
gdomap 538 udp gdomap [Richard_Frith_Macdon] [Richard_Frith_Macdon]
apertus-ldp 539 udp Apertus Technologies Load Determination
uucp 540 udp uucpd
uucp-rlogin 541 udp uucp-rlogin [Stuart_Lynne] [Stuart_Lynne]
commerce 542 udp commerce [Randy_Epstein] [Randy_Epstein]
klogin 543 udp
kshell 544 udp krcmd
appleqtcsrvr 545 udp appleqtcsrvr [Murali_Ranganathan] [Murali_Ranganathan]
dhcpv6-client 546 udp DHCPv6 Client [IESG] [IETF_Chair] 2018-05-21 [RFC-ietf-dhc-rfc8415bis-12]
dhcpv6-server 547 udp DHCPv6 Server [IESG] [IETF_Chair] 2018-05-21 [RFC-ietf-dhc-rfc8415bis-12]
afpovertcp 548 udp AFP over TCP [Leland_Wallace] [Leland_Wallace] Defined TXT keys: u=<username> p=<password> path=<path>
idfp 549 udp IDFP [Ramana_Kovi] [Ramana_Kovi]
new-rwho 550 udp new-who [n/a]
cybercash 551 udp cybercash [Donald_E_Eastlake] [Donald_E_Eastlake] [RFC1898]
devshr-nts 552 udp DeviceShare [Benjamin_Rosenberg] [Benjamin_Rosenberg]
pirp 553 udp pirp [D_J_Bernstein] [D_J_Bernstein]
rtsp 554 udp Real Time Streaming Protocol (RTSP) [Rob_Lanphier] [Rob_Lanphier]
dsf 555 udp
remotefs 556 udp rfs server

Contact Information

ID Name Organization Contact URI Last Updated
[Alain_Durand] Alain Durand mailto:Alain.Durand&imag.fr
[Alan_Ungar] Alan Ungar mailto:aungar&farradyne.com
[Andreas_Heidemann] Andreas Heidemann mailto:a.heidemann&ais-gmbh.de
[Art_Cancro] Art Cancro mailto:ajc&citadel.org 2015-02-18
[Benjamin_Rosenberg] Benjamin Rosenberg mailto:brosenberg&advsyscon.com
[Beverly_Moody] Beverly Moody mailto:Beverly_Moody&stercomm.com
[Bill_Reding] Bill Reding mailto:redingb&nwdt.natwest.co.uk
[Bill_Simpson_2] Bill Simpson mailto:Bill.Simpson&um.cc.umich.edu
[Brad_Wright] Brad Wright mailto:bradwr&microsoft.com
[Brian_Tackett] Brian Tackett mailto:cym&acrux.net
[D_J_Bernstein] D. J. Bernstein mailto:ports&box.cr.yp.to 2018-04-05
[Daniel_Mavrakis] Daniel Mavrakis mailto:system&venus.mctel.fr
[David_Misunas] David Misunas mailto:DMisunas&micom.com
[Dennis_Batchelder] Dennis Batchelder mailto:dennis&capres.com
[Dennis_Dube] Dennis Dube mailto:dennis.dube&schneider-electric.com 2014-06-10
[Diane_Downie] Diane Downie mailto:downie&jibe.mv.com
[Dino_Farinacci] Dino Farinacci mailto:dino&cisco.com 2008-08-21
[Don_Provan_2] Don Provan mailto:donp&sjf.novell.com
[Donald_E_Eastlake] Donald E. Eastlake 3rd mailto:d3e3e3&gmail.com
[Doug_Rosenthal] Doug Rosenthal mailto:rosenthl&krypton.einet.net
[Ed_Kress] Ed Kress mailto:eskress&thinknet.com
[Faith_Zack] Faith Zack mailto:faithz&sco.com
[Ferdi_Ladeira] Ferdi Ladeira mailto:f.lad.mail&gmail.com 2022-01-25
[Gary_Lewis] Gary Lewis mailto:GaryL&hq.mylex.com
[Gilles_Gameiro] Gilles Gameiro mailto:ggameiro&birdland.com
[Greg_Hudson_2] Greg Hudson mailto:ghudson&mit.edu 2023-11-17
[Henry_Strickland] Henry Strickland mailto:strick&yak.net
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Jean_Michel_URSCH] Jean-Michel URSCH mailto:ursch&taec.enet.dec.com
[Jeff_M_Michaud] Jeff M.Michaud mailto:michaud&zk3.dec.com
[JG_Heithcock] JG Heithcock Retrospect, Inc. mailto:JG.Heithcock&retrospect.com 2012-02-02
[Jim_Jennings] Jim Jennings tel:+1-708-538-7241
[John_Rainford] John Rainford mailto:jrainford&passgo.com
[Jon_Saperia] Jon Saperia mailto:saperia&bgs.com
[Juliana_Hsu] Juliana Hsu mailto:jhsu&ca.ibm.com
[Keith_J_Alphonso] Keith J. Alphonso mailto:alphonso&ncs-ssc.com
[Kevin_Mooney] Kevin Mooney mailto:kevinm&bfs.unibol.com
[LJK] LJK Software, Cambridge, Massachusetts mailto:support&ljk.com
[Laurent_Domenech] Laurent Domenech Opalis mailto:ldomenech&opalis.com
[Leland_Wallace] Leland Wallace mailto:randall&apple.com
[Mamoru_Ito] Mamoru Ito mailto:Ito&pcnet.ks.pfu.co.jp
[Mark_H_Needleman] Mark H. Needleman mailto:markn&sirsi.com
[Mark_Schertler] Mark Schertler mailto:mjs&tycho.ncsc.mil
[Max_Morris] Max Morris mailto:maxm&microsoft.com
[Michael_Zunke] Michael Zunke mailto:michael.zunke&ealaddin.com 2010-07-23
[Mike_Marshburn] Mike Marshburn mailto:paul&softarc.com
[Mike_Rieker] Mike Rieker mailto:mikea&sp32.com
[modbus.org] modbus.org mailto:rbelliardi&modbus.org 2014-06-10
[Murali_Ranganathan] Murali Ranganathan mailto:murali_ranganathan&quickmail.apple.com
[Paul_Santinelli_Jr] Paul Santinelli Jr. mailto:psantinelli&narrative.com
[Peter_Higginson] Peter Higginson mailto:higginson&mail.dec.com
[Philippe_Gilbert] Philippe Gilbert mailto:pgilbert&cal.fr
[POV_Team_Co_ordinato] POV-Team Co-ordinator mailto:iana-port.remove-spamguard&povray.org
[Ramana_Kovi] Ramana Kovi mailto:ramana&kovi.com
[Rami_Rubin] Rami Rubin mailto:rami&hybrid.com
[Randall_Dow] Randall Dow mailto:rand&randix.net
[Randy_Epstein] Randy Epstein mailto:randy&epstein.com 2023-10-18
[Retrospect_Inc] Retrospect, Inc. mailto:JG.Heithcock&retrospect.com 2012-02-02
[Richard_Frith_Macdon] Richard Frith-Macdonald mailto:richard&brainstorm.co.uk
[Rick_Yazwinski] Rick Yazwinski mailto:ricky&solect.com
[Rob_Janssen] Rob Janssen mailto:rob&sys3.pe1chl.ampr.org
[Rob_Lanphier] Rob Lanphier mailto:robla&prognet.com
[Robert_E_Minnear] Robert E. Minnear mailto:minnear&ipsilon.com
[Robert_Ford] Robert Ford mailto:robert&intrinsa.com
[Robert_Ullmann_2] Robert Ullmann mailto:Robert_Ullmann/CAM/Lotus.LOTUS@crd.lotus.com
[Roland_Hedberg] Roland Hedberg mailto:Roland.Hedberg&umdac.umu.se
[Scott_Narveson] Scott Narveson mailto:sjn&cray.com
[Scott_Powell] Scott Powell mailto:spowell&openhorizon.com
[Steve_Favor] Steve Favor mailto:sfavor&tigger.intecom.com
[Stuart_Lynne] Stuart Lynne mailto:sl&wimsey.com
[Toerless_Eckert] Toerless Eckert mailto:eckert&cisco.com
[Troy_Morrison] Troy Morrison mailto:troy&graphon.com
[Ulli_Horlacher] Ulli Horlacher mailto:framstag&rus.uni-stuttgart.de
[Uwe_Honermann] Uwe Honermann mailto:u.honermann&windream.com
[gary] mailto:gary&airsoft.com