Service Name and Transport Protocol Port Number Registry

Last Updated
2026-05-11
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
discard 9 dccp Discard [Eddie_Kohler] [Eddie_Kohler] [RFC4340] 1145656131
smtp 25 tcp Simple Mail Transfer [IESG] [IETF_Chair] 2017-06-05 [RFC-ietf-emailcore-rfc5321bis-43]
smtp 25 udp Simple Mail Transfer [IESG] [IETF_Chair] 2017-06-05 [RFC-ietf-emailcore-rfc5321bis-43]
nicname 43 tcp Who Is
nicname 43 udp Who Is
imap 143 tcp Internet Message Access Protocol [IESG] [IETF_Chair] 2021-02-22 [RFC3501][RFC9051]
143 udp Reserved 2021-02-22 [RFC9051]
sur-meas 243 tcp Survey Measurement [Dave_Clark] [Dave_Clark]
sur-meas 243 udp Survey Measurement [Dave_Clark] [Dave_Clark]
334-343 Unassigned
utmpsd 430 tcp UTMPSD
utmpsd 430 udp UTMPSD
utmpcd 431 tcp UTMPCD
utmpcd 431 udp UTMPCD
iasd 432 tcp IASD [Nir_Baroz] [Nir_Baroz]
iasd 432 udp IASD [Nir_Baroz] [Nir_Baroz]
nnsp 433 tcp NNTP for transit servers (NNSP) [IESG] [IETF_Chair] 2018-07-06 [RFC3977]
nnsp 433 udp NNTP for transit servers (NNSP) [IESG] [IETF_Chair] 2018-07-06 [RFC3977]
mobileip-agent 434 tcp MobileIP-Agent
mobileip-agent 434 udp MobileIP-Agent
mobilip-mn 435 tcp MobilIP-MN [Kannan_Alagappan_2] [Kannan_Alagappan_2]
mobilip-mn 435 udp MobilIP-MN [Kannan_Alagappan_2] [Kannan_Alagappan_2]
dna-cml 436 tcp DNA-CML [Dan_Flowers] [Dan_Flowers]
dna-cml 436 udp DNA-CML [Dan_Flowers] [Dan_Flowers]
comscm 437 tcp comscm [Jim_Teague] [Jim_Teague]
comscm 437 udp comscm [Jim_Teague] [Jim_Teague]
dsfgw 438 tcp dsfgw [Andy_McKeen] [Andy_McKeen]
dsfgw 438 udp dsfgw [Andy_McKeen] [Andy_McKeen]
dasp 439 tcp dasp [Thomas_Obermair] [Thomas_Obermair]
dasp 439 udp dasp [Thomas_Obermair] [Thomas_Obermair]
https 443 tcp http protocol over TLS/SSL [IESG] [IETF_Chair] 2021-10-01 [RFC9110]
https 443 udp http protocol over TLS/SSL [IESG] [IETF_Chair] 2021-10-01 [RFC9110]
https 443 sctp HTTPS [Randall_Stewart] [Randall_Stewart] 2022-02-07 [RFC9260]
klogin 543 tcp
klogin 543 udp
sanity 643 tcp SANity [Peter_Viscarola] [Peter_Viscarola]
sanity 643 udp SANity [Peter_Viscarola] [Peter_Viscarola]
743 Unassigned
iscsi 860 tcp iSCSI [IESG] [IETF_Chair] 2013-08-27 [RFC7143]
iscsi 860 udp iSCSI [IESG] [IETF_Chair] 2013-08-27 [RFC7143]
kink 910 tcp Kerberized Internet Negotiation of Keys (KINK) [RFC4430]
kink 910 udp Kerberized Internet Negotiation of Keys (KINK) [RFC4430]
boinc-client 1043 tcp BOINC Client Control [David_Anderson] [David_Anderson] 2004-11
boinc-client 1043 udp BOINC Client Control [David_Anderson] [David_Anderson] 2004-11
imyx 1143 tcp Infomatryx Exchange [David_Walling] [David_Walling] 2006-03
imyx 1143 udp Infomatryx Exchange [David_Walling] [David_Walling] 2006-03
serialgateway 1243 tcp SerialGateway [Stephen_LaValley] [Stephen_LaValley]
serialgateway 1243 udp SerialGateway [Stephen_LaValley] [Stephen_LaValley]
re101 1343 tcp re101 [Doriano_Blengino] [Doriano_Blengino]
re101 1343 udp re101 [Doriano_Blengino] [Doriano_Blengino]
tpdu 1430 tcp Hypercom TPDU [Noor_Chowdhury] [Noor_Chowdhury]
tpdu 1430 udp Hypercom TPDU [Noor_Chowdhury] [Noor_Chowdhury]
rgtp 1431 tcp Reverse Gossip Transport [Ian_Jackson] [Ian_Jackson]
rgtp 1431 udp Reverse Gossip Transport [Ian_Jackson] [Ian_Jackson]
blueberry-lm 1432 tcp Blueberry Software License Manager [Steve_Beigel] [Steve_Beigel]
blueberry-lm 1432 udp Blueberry Software License Manager [Steve_Beigel] [Steve_Beigel]
ms-sql-s 1433 tcp Microsoft-SQL-Server
ms-sql-s 1433 udp Microsoft-SQL-Server
ms-sql-m 1434 tcp Microsoft-SQL-Monitor [Peter_Hussey] [Peter_Hussey]
ms-sql-m 1434 udp Microsoft-SQL-Monitor [Peter_Hussey] [Peter_Hussey]
ibm-cics 1435 tcp IBM CICS [Geoff_Meacock] [Geoff_Meacock]
ibm-cics 1435 udp IBM CICS [Geoff_Meacock] [Geoff_Meacock]
saism 1436 tcp Satellite-data Acquisition System 2 [Bill_Taylor] [Bill_Taylor]
saism 1436 udp Satellite-data Acquisition System 2 [Bill_Taylor] [Bill_Taylor]
tabula 1437 tcp Tabula [Marcelo_Einhorn] [Marcelo_Einhorn]
tabula 1437 udp Tabula [Marcelo_Einhorn] [Marcelo_Einhorn]
eicon-server 1438 tcp Eicon Security Agent/Server
eicon-server 1438 udp Eicon Security Agent/Server
eicon-x25 1439 tcp Eicon X25/SNA Gateway
eicon-x25 1439 udp Eicon X25/SNA Gateway
ies-lm 1443 tcp Integrated Engineering Software [David_Tong] [David_Tong]
ies-lm 1443 udp Integrated Engineering Software [David_Tong] [David_Tong]
simba-cs 1543 tcp simba-cs [Betsy_Alexander] [Betsy_Alexander]
simba-cs 1543 udp simba-cs [Betsy_Alexander] [Betsy_Alexander]
isis-ambc 1643 tcp isis-ambc [Ken_Chapman] [Ken_Chapman]
isis-ambc 1643 udp isis-ambc [Ken_Chapman] [Ken_Chapman]
cinegrfx-lm 1743 tcp Cinema Graphics License Manager [Rodney_Iwashina] [Rodney_Iwashina]
cinegrfx-lm 1743 udp Cinema Graphics License Manager [Rodney_Iwashina] [Rodney_Iwashina]
netopia-vo5 1843 tcp netopia-vo5 [Marc_Epard] [Marc_Epard]
netopia-vo5 1843 udp netopia-vo5 [Marc_Epard] [Marc_Epard]
beeyond-media 1943 tcp Beeyond Media [Bob_Deblier] [Bob_Deblier]
beeyond-media 1943 udp Beeyond Media [Bob_Deblier] [Bob_Deblier]
isis-bcast 2043 tcp isis-bcast [Ken_Chapman] [Ken_Chapman]
isis-bcast 2043 udp isis-bcast [Ken_Chapman] [Ken_Chapman]
lv-jc 2143 tcp Live Vault Job Control
lv-jc 2143 udp Live Vault Job Control
magicom 2243 tcp Magicom Protocol [Yossi_Appleboum] [Yossi_Appleboum]
magicom 2243 udp Magicom Protocol [Yossi_Appleboum] [Yossi_Appleboum]
nati-logos 2343 tcp nati logos [James_Juhasz] [James_Juhasz]
nati-logos 2343 udp nati logos [James_Juhasz] [James_Juhasz]
venus 2430 tcp venus
venus 2430 udp venus
venus-se 2431 tcp venus-se
venus-se 2431 udp venus-se
codasrv 2432 tcp codasrv
codasrv 2432 udp codasrv
codasrv-se 2433 tcp codasrv-se [Robert_Watson] [Robert_Watson]
codasrv-se 2433 udp codasrv-se [Robert_Watson] [Robert_Watson]
pxc-epmap 2434 tcp pxc-epmap [Jun_Nakamura] [Jun_Nakamura]
pxc-epmap 2434 udp pxc-epmap [Jun_Nakamura] [Jun_Nakamura]

Contact Information

ID Name Organization Contact URI Last Updated
[Andy_McKeen] Andy McKeen mailto:mckeen&osf.org
[Betsy_Alexander] Betsy Alexander tel:+1-604-681-4549
[Bill_Taylor] Bill Taylor mailto:sais&ssec.wisc.edu
[Bob_Deblier] Bob Deblier mailto:bob&virtualunlimited.com
[Dan_Flowers] Dan Flowers mailto:flowers&smaug.lkg.dec.com
[Dave_Clark] Dave Clark mailto:ddc&lcs.mit.edu
[David_Anderson] David Anderson mailto:davea&ssl.berkeley.edu 2004-11
[David_Tong] David Tong mailto:David_Tong&integrated.mb.ca
[David_Walling] David Walling mailto:sylvanhollow&yahoo.com 2006-03
[Doriano_Blengino] Doriano Blengino mailto:tecnico_remove_&_remove_xonelectronics.it
[Eddie_Kohler] Eddie Kohler IETF dccp WG mailto:kohler&cs.ucla.edu
[Geoff_Meacock] Geoff Meacock mailto:gbibmswl&ibmmail.com
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Ian_Jackson] Ian Jackson mailto:iwj&cam-orl.co.uk
[James_Juhasz] James Juhasz mailto:james.juhasz&ni.com
[Jim_Teague] Jim Teague mailto:teague&zso.dec.com
[Jun_Nakamura] Jun Nakamura mailto:jnakamur&cp10.es.xerox.com
[Kannan_Alagappan_2] Kannan Alagappan mailto:kannan&sejour.lkg.dec.com
[Ken_Chapman] Ken Chapman mailto:kchapman&isis.com
[Marc_Epard] Marc Epard mailto:marc&netopia.com
[Marcelo_Einhorn] Marcelo Einhorn mailto:KGUNE%25HUJIVM1.bitnet@taunivm.tau.ac.il
[Nir_Baroz] Nir Baroz mailto:nbaroz&encore.com
[Noor_Chowdhury] Noor Chowdhury mailto:noor&hypercom.com
[Peter_Hussey] Peter Hussey mailto:peterhus&microsoft.com
[Peter_Viscarola] Peter Viscarola mailto:PeterGV&osr.com
[Randall_Stewart] Randall Stewart IETF TSVWG mailto:rrs&lakerest.net
[Robert_Watson] Robert Watson mailto:robert&cyrus.watson.org
[Rodney_Iwashina] Rodney Iwashina mailto:rodney&cyclone.rfx.com
[Stephen_LaValley] Stephen LaValley mailto:lavalley&lucent.com
[Steve_Beigel] Steve Beigel mailto:ublueb!steve&uunet.uu.net
[Thomas_Obermair] Thomas Obermair mailto:tommy&inlab.m.eunet.de
[Yossi_Appleboum] Yossi Appleboum mailto:yossia&magicom.co.il