Internet Assigned Numbers Authority

Service Name and Transport Protocol Port Number Registry

Last Updated
2025-04-07
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
4 tcp Unassigned
4 udp Unassigned
discard 9 dccp Discard [Eddie_Kohler] [Eddie_Kohler] [RFC4340] 1145656131
14 tcp Unassigned
14 udp Unassigned
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>
telnet 23 tcp Telnet [Jon_Postel] [Jon_Postel] [RFC854] Defined TXT keys: u=<username> p=<password>
telnet 23 udp Telnet [Jon_Postel] [Jon_Postel] [RFC854] Defined TXT keys: u=<username> p=<password>
24 tcp any private mail system [Rick_Adams] [Rick_Adams]
24 udp any private mail system [Rick_Adams] [Rick_Adams]
34 tcp Unassigned
34 udp Unassigned
40 tcp Unassigned
40 udp Unassigned
graphics 41 tcp Graphics
graphics 41 udp Graphics
name 42 tcp Host Name Server
name 42 udp Host Name Server
nameserver 42 tcp Host Name Server
nameserver 42 udp Host Name Server
nicname 43 tcp Who Is
nicname 43 udp Who Is
mpm-flags 44 tcp MPM FLAGS Protocol
mpm-flags 44 udp MPM FLAGS Protocol
mpm 45 tcp Message Processing Module [recv]
mpm 45 udp Message Processing Module [recv]
mpm-snd 46 tcp MPM [default send] [Jon_Postel] [Jon_Postel]
mpm-snd 46 udp MPM [default send] [Jon_Postel] [Jon_Postel]
47 tcp Reserved 2017-05-18 This entry has been removed on 2017-05-18.
47 udp Reserved 2017-05-18 This entry has been removed on 2017-05-18.
auditd 48 tcp Digital Audit Daemon [Larry_Scott] [Larry_Scott]
auditd 48 udp Digital Audit Daemon [Larry_Scott] [Larry_Scott]
tacacs 49 tcp Login Host Protocol (TACACS) [Pieter_Ditmars] [Pieter_Ditmars]
tacacs 49 udp Login Host Protocol (TACACS) [Pieter_Ditmars] [Pieter_Ditmars]
51 Reserved 2013-05-24 This entry is being removed on 2013-05-24.
xns-ch 54 tcp XNS Clearinghouse [Susie_Armstrong] [Susie_Armstrong]
xns-ch 54 udp XNS Clearinghouse [Susie_Armstrong] [Susie_Armstrong]
covia 64 tcp Communications Integrator (CI) [Dan_Smith] [Dan_Smith]
covia 64 udp Communications Integrator (CI) [Dan_Smith] [Dan_Smith]
netrjs-4 74 tcp Remote Job Service [Bob_Braden] [Bob_Braden]
netrjs-4 74 udp Remote Job Service [Bob_Braden] [Bob_Braden]
finger 79 tcp Finger [David_Zimmerman] [David_Zimmerman] Unauthorized use by some mail users (see [RFC4146] for details)
finger 79 udp Finger [David_Zimmerman] [David_Zimmerman] Unauthorized use by some mail users (see [RFC4146] for details)
ctf 84 tcp Common Trace Facility [Hugh_Thomas] [Hugh_Thomas]
ctf 84 udp Common Trace Facility [Hugh_Thomas] [Hugh_Thomas]
kerberos 88 tcp Kerberos [B_Clifford_Neuman] [B_Clifford_Neuman] 2022-02-18 [RFC4120]
kerberos 88 udp Kerberos [B_Clifford_Neuman] [B_Clifford_Neuman] 2022-02-18 [RFC4120]
objcall 94 tcp Tivoli Object Dispatcher [Tom_Bereiter] [Tom_Bereiter]
objcall 94 udp Tivoli Object Dispatcher [Tom_Bereiter] [Tom_Bereiter]
acr-nema 104 tcp ACR-NEMA Digital Imag. & Comm. 300 [Patrick_McNamee] [Patrick_McNamee]
acr-nema 104 udp ACR-NEMA Digital Imag. & Comm. 300 [Patrick_McNamee] [Patrick_McNamee]
114 unassigned Deprecated June 2004
ansatrader 124 tcp ANSA REX Trader [Nicola_J_Howarth] [Nicola_J_Howarth]
ansatrader 124 udp ANSA REX Trader [Nicola_J_Howarth] [Nicola_J_Howarth]
ingres-net 134 tcp INGRES-NET Service [Mike_Berrow] [Mike_Berrow]
ingres-net 134 udp INGRES-NET Service [Mike_Berrow] [Mike_Berrow]
emfis-data 140 tcp EMFIS Data Service
emfis-data 140 udp EMFIS Data Service
emfis-cntl 141 tcp EMFIS Control Service [Gerd_Beling] [Gerd_Beling]
emfis-cntl 141 udp EMFIS Control Service [Gerd_Beling] [Gerd_Beling]
bl-idm 142 tcp Britton-Lee IDM [Susie_Snitzer] [Susie_Snitzer]
bl-idm 142 udp Britton-Lee IDM [Susie_Snitzer] [Susie_Snitzer]
imap 143 tcp Internet Message Access Protocol [IESG] [IETF_Chair] 2021-02-22 [RFC3501][RFC9051]
143 udp Reserved 2021-02-22 [RFC9051]
uma 144 tcp Universal Management Architecture [Jay_Whitney] [Jay_Whitney]
uma 144 udp Universal Management Architecture [Jay_Whitney] [Jay_Whitney]
uaac 145 tcp UAAC Protocol [David_A_Gomberg] [David_A_Gomberg]
uaac 145 udp UAAC Protocol [David_A_Gomberg] [David_A_Gomberg]
iso-tp0 146 tcp ISO-IP0
iso-tp0 146 udp ISO-IP0
iso-ip 147 tcp ISO-IP [Marshall_Rose] [Marshall_Rose]
iso-ip 147 udp ISO-IP [Marshall_Rose] [Marshall_Rose]
jargon 148 tcp Jargon [Bill_Weinman] [Bill_Weinman]
jargon 148 udp Jargon [Bill_Weinman] [Bill_Weinman]
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]
netsc-prod 154 tcp NETSC
netsc-prod 154 udp NETSC
cmip-agent 164 tcp CMIP/TCP Agent [Amatzia_Ben_Artzi] [Amatzia_Ben_Artzi]
cmip-agent 164 udp CMIP/TCP Agent [Amatzia_Ben_Artzi] [Amatzia_Ben_Artzi]
mailq 174 tcp MAILQ [Rayan_Zachariassen] [Rayan_Zachariassen]
mailq 174 udp MAILQ [Rayan_Zachariassen] [Rayan_Zachariassen]
ocserver 184 tcp OCServer [Jerrilynn_Okamura] [Jerrilynn_Okamura]
ocserver 184 udp OCServer [Jerrilynn_Okamura] [Jerrilynn_Okamura]
irc 194 tcp Internet Relay Chat Protocol [Jarkko_Oikarinen] [Jarkko_Oikarinen]
irc 194 udp Internet Relay Chat Protocol [Jarkko_Oikarinen] [Jarkko_Oikarinen]
at-echo 204 tcp AppleTalk Echo
at-echo 204 udp AppleTalk Echo
914c-g 211 tcp Texas Instruments 914C/G Terminal

IANA assigned this well-formed service name as a replacement for "914c/g".
[Bill_Harrell] [Bill_Harrell]
914c/g 211 tcp Texas Instruments 914C/G Terminal [Bill_Harrell] [Bill_Harrell] This entry is an alias to "914c-g". This entry is now historic, not usable for use with many common service discovery mechanisms.
914c-g 211 udp Texas Instruments 914C/G Terminal

IANA assigned this well-formed service name as a replacement for "914c/g".
[Bill_Harrell] [Bill_Harrell]
914c/g 211 udp Texas Instruments 914C/G Terminal [Bill_Harrell] [Bill_Harrell] This entry is an alias to "914c-g". This entry is now historic, not usable for use with many common service discovery mechanisms.
vmpwscs 214 tcp VM PWSCS [Dan_Shia] [Dan_Shia]
vmpwscs 214 udp VM PWSCS [Dan_Shia] [Dan_Shia]
masqdialer 224 tcp masqdialer [Charles_Wright] [Charles_Wright] Possible Conflict of Port 222 with "Masqdialer"
masqdialer 224 udp masqdialer [Charles_Wright] [Charles_Wright] Possible Conflict of Port 222 with "Masqdialer"
225-241 Reserved 2024-12-20 [RFC1060]
direct 242 tcp Direct [Herb_Sutter] [Paul_Horton]
direct 242 udp Direct [Herb_Sutter] [Paul_Horton]

Contact Information

ID Name Organization Contact URI Last Updated
[Albert_G_Broscius] Albert G. Broscius mailto:broscius&dsl.cis.upenn.edu
[Amatzia_Ben_Artzi] Amatzia Ben-Artzi
[B_Clifford_Neuman] B. Clifford Neuman mailto:bcn&isi.edu 2022-02-18
[Bill_Harrell] Bill Harrell
[Bill_Weinman] Bill Weinman mailto:wew&bearnet.com
[Bob_Braden] Bob Braden mailto:Braden&isi.edu
[Charles_Wright] Charles Wright mailto:cpwright&villagenet.com
[Dan_Shia] Dan Shia mailto:dset!shia&uunet.uu.net
[Dan_Smith] Dan Smith mailto:dan.smith&den.galileo.com
[David_A_Gomberg] David A. Gomberg mailto:gomberg&gateway.mitre.org
[David_Zimmerman] David Zimmerman mailto:dpz&rutgers.edu
[Eddie_Kohler] Eddie Kohler IETF dccp WG mailto:kohler&cs.ucla.edu
[Gerd_Beling] Gerd Beling mailto:GBELING&isi.edu
[Herb_Sutter] Herb Sutter mailto:HerbS&cntc.com
[Hugh_Thomas] Hugh Thomas mailto:thomas&oils.enet.dec.com
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Jarkko_Oikarinen] Jarkko Oikarinen mailto:jto&tolsun.oulu.fi
[Jay_Whitney] Jay Whitney mailto:jw&powercenter.com
[Jerrilynn_Okamura] Jerrilynn Okamura
[Jon_Postel] Jon Postel mailto:postel&isi.edu
[Larry_Scott] Larry Scott mailto:scott&zk3.dec.com
[Marshall_Rose] Marshall Rose mailto:mrose17&gmail.com 2024-07-29
[Mike_Berrow] Mike Berrow
[Nicola_J_Howarth] Nicola J. Howarth mailto:njh&ansa.co.uk
[Patrick_McNamee] Patrick McNamee
[Paul_Horton] Paul Horton mailto:paul.horton&dxstro.com 2016-05-18
[Pieter_Ditmars] Pieter Ditmars mailto:pditmars&bbn.com
[Rayan_Zachariassen] Rayan Zachariassen mailto:rayan&ai.toronto.edu
[Rick_Adams] Rick Adams mailto:rick&uunet.uu.net
[Susie_Armstrong] Susie Armstrong mailto:Armstrong.wbst128@xerox
[Susie_Snitzer] Susie Snitzer
[Tom_Bereiter] Tom Bereiter