Internet Assigned Numbers Authority

Service Name and Transport Protocol Port Number Registry

Last Updated
2024-12-20
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
siam 498 udp siam [Philippe_Gilbert] [Philippe_Gilbert]
iso-ill 499 tcp ISO ILL Protocol [Mark_H_Needleman] [Mark_H_Needleman]
iso-ill 499 udp ISO ILL Protocol [Mark_H_Needleman] [Mark_H_Needleman]
isakmp 500 tcp isakmp [Mark_Schertler] [Mark_Schertler]
isakmp 500 udp isakmp [Mark_Schertler] [Mark_Schertler]
stmf 501 tcp STMF [Alan_Ungar] [Alan_Ungar]
stmf 501 udp STMF [Alan_Ungar] [Alan_Ungar]
mbap 502 tcp Modbus Application Protocol [modbus.org] [Dennis_Dube] 2014-06-10
mbap 502 udp Modbus Application Protocol [modbus.org] [Dennis_Dube] 2014-06-10
intrinsa 503 tcp Intrinsa [Robert_Ford] [Robert_Ford]
intrinsa 503 udp Intrinsa [Robert_Ford] [Robert_Ford]
citadel 504 tcp citadel [Art_Cancro] [Art_Cancro]
citadel 504 udp citadel [Art_Cancro] [Art_Cancro]
mailbox-lm 505 tcp mailbox-lm [Beverly_Moody] [Beverly_Moody]
mailbox-lm 505 udp mailbox-lm [Beverly_Moody] [Beverly_Moody]
ohimsrv 506 tcp ohimsrv [Scott_Powell] [Scott_Powell]
ohimsrv 506 udp ohimsrv [Scott_Powell] [Scott_Powell]
crs 507 tcp crs [Brad_Wright] [Brad_Wright]
crs 507 udp crs [Brad_Wright] [Brad_Wright]
xvttp 508 tcp xvttp [Keith_J_Alphonso] [Keith_J_Alphonso]
xvttp 508 udp xvttp [Keith_J_Alphonso] [Keith_J_Alphonso]
snare 509 tcp snare [Dennis_Batchelder] [Dennis_Batchelder]
snare 509 udp snare [Dennis_Batchelder] [Dennis_Batchelder]
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
efs 520 tcp extended file name server
router 520 udp local routing process (on site); uses variant of Xerox NS routing information protocol - RIP
ripng 521 tcp ripng [Robert_E_Minnear] [Robert_E_Minnear]
ripng 521 udp ripng [Robert_E_Minnear] [Robert_E_Minnear]
ulp 522 tcp ULP [Max_Morris] [Max_Morris]
ulp 522 udp ULP [Max_Morris] [Max_Morris]
ibm-db2 523 tcp IBM-DB2 [Juliana_Hsu] [Juliana_Hsu]
ibm-db2 523 udp IBM-DB2 [Juliana_Hsu] [Juliana_Hsu]
ncp 524 tcp NCP [Don_Provan_2] [Don_Provan_2]
ncp 524 udp NCP [Don_Provan_2] [Don_Provan_2]
timed 525 tcp timeserver
timed 525 udp timeserver
tempo 526 tcp newdate
tempo 526 udp newdate
stx 527 tcp Stock IXChange [Ferdi_Ladeira] [Ferdi_Ladeira] 2022-01-25
stx 527 udp Stock IXChange [Ferdi_Ladeira] [Ferdi_Ladeira] 2022-01-25
custix 528 tcp Customer IXChange [Ferdi_Ladeira] [Ferdi_Ladeira] 2022-01-25
custix 528 udp Customer IXChange [Ferdi_Ladeira] [Ferdi_Ladeira] 2022-01-25
irc-serv 529 tcp IRC-SERV [Brian_Tackett] [Brian_Tackett]
irc-serv 529 udp IRC-SERV [Brian_Tackett] [Brian_Tackett]
courier 530 tcp rpc
courier 530 udp rpc
conference 531 tcp chat
conference 531 udp chat
netnews 532 tcp readnews
netnews 532 udp readnews
netwall 533 tcp for emergency broadcasts [Andreas_Heidemann] [Andreas_Heidemann]
netwall 533 udp for emergency broadcasts [Andreas_Heidemann] [Andreas_Heidemann]
windream 534 tcp windream Admin [Uwe_Honermann] [Uwe_Honermann]
windream 534 udp windream Admin [Uwe_Honermann] [Uwe_Honermann]
iiop 535 tcp iiop [Jeff_M_Michaud] [Jeff_M_Michaud]
iiop 535 udp iiop [Jeff_M_Michaud] [Jeff_M_Michaud]
opalis-rdv 536 tcp opalis-rdv [Laurent_Domenech] [Laurent_Domenech]
opalis-rdv 536 udp opalis-rdv [Laurent_Domenech] [Laurent_Domenech]
nmsp 537 tcp Networked Media Streaming Protocol [Paul_Santinelli_Jr] [Paul_Santinelli_Jr]
nmsp 537 udp Networked Media Streaming Protocol [Paul_Santinelli_Jr] [Paul_Santinelli_Jr]
gdomap 538 tcp gdomap [Richard_Frith_Macdon] [Richard_Frith_Macdon]
gdomap 538 udp gdomap [Richard_Frith_Macdon] [Richard_Frith_Macdon]
apertus-ldp 539 tcp Apertus Technologies Load Determination
apertus-ldp 539 udp Apertus Technologies Load Determination
uucp 540 tcp uucpd
uucp 540 udp uucpd
uucp-rlogin 541 tcp uucp-rlogin [Stuart_Lynne] [Stuart_Lynne]
uucp-rlogin 541 udp uucp-rlogin [Stuart_Lynne] [Stuart_Lynne]
commerce 542 tcp commerce [Randy_Epstein] [Randy_Epstein]
commerce 542 udp commerce [Randy_Epstein] [Randy_Epstein]
klogin 543 tcp
klogin 543 udp
kshell 544 tcp krcmd
kshell 544 udp krcmd
appleqtcsrvr 545 tcp appleqtcsrvr [Murali_Ranganathan] [Murali_Ranganathan]
appleqtcsrvr 545 udp appleqtcsrvr [Murali_Ranganathan] [Murali_Ranganathan]
dhcpv6-client 546 tcp DHCPv6 Client
dhcpv6-client 546 udp DHCPv6 Client [IESG] [IETF_Chair] 2018-05-21 [RFC8415]
dhcpv6-server 547 tcp DHCPv6 Server [IESG] [IETF_Chair] 2018-05-21 [RFC5460]
dhcpv6-server 547 udp DHCPv6 Server [IESG] [IETF_Chair] 2018-05-21 [RFC8415]
afpovertcp 548 tcp AFP over TCP [Leland_Wallace] [Leland_Wallace] Defined TXT keys: u=<username> p=<password> path=<path>

Contact Information

ID Name Organization Contact URI Last Updated
[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
[Beverly_Moody] Beverly Moody mailto:Beverly_Moody&stercomm.com
[Brad_Wright] Brad Wright mailto:bradwr&microsoft.com
[Brian_Tackett] Brian Tackett mailto:cym&acrux.net
[Daniel_Mavrakis] Daniel Mavrakis mailto:system&venus.mctel.fr
[Dennis_Batchelder] Dennis Batchelder mailto:dennis&capres.com
[Dennis_Dube] Dennis Dube mailto:dennis.dube&schneider-electric.com 2014-06-10
[Don_Provan_2] Don Provan mailto:donp&sjf.novell.com
[Ferdi_Ladeira] Ferdi Ladeira mailto:f.lad.mail&gmail.com 2022-01-25
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Jeff_M_Michaud] Jeff M.Michaud mailto:michaud&zk3.dec.com
[John_Rainford] John Rainford mailto:jrainford&passgo.com
[Juliana_Hsu] Juliana Hsu mailto:jhsu&ca.ibm.com
[Keith_J_Alphonso] Keith J. Alphonso mailto:alphonso&ncs-ssc.com
[Laurent_Domenech] Laurent Domenech Opalis mailto:ldomenech&opalis.com
[Leland_Wallace] Leland Wallace mailto:randall&apple.com
[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
[Mike_Marshburn] Mike Marshburn mailto:paul&softarc.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
[Philippe_Gilbert] Philippe Gilbert mailto:pgilbert&cal.fr
[Randy_Epstein] Randy Epstein mailto:randy&epstein.com 2023-10-18
[Richard_Frith_Macdon] Richard Frith-Macdonald mailto:richard&brainstorm.co.uk
[Robert_E_Minnear] Robert E. Minnear mailto:minnear&ipsilon.com
[Robert_Ford] Robert Ford mailto:robert&intrinsa.com
[Scott_Powell] Scott Powell mailto:spowell&openhorizon.com
[Stuart_Lynne] Stuart Lynne mailto:sl&wimsey.com
[Uwe_Honermann] Uwe Honermann mailto:u.honermann&windream.com