Internet Assigned Numbers Authority

Service Name and Transport Protocol Port Number Registry

Last Updated
2025-08-15
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
discard 9 tcp Discard [Jon_Postel] [Jon_Postel]
discard 9 udp Discard [Jon_Postel] [Jon_Postel]
discard 9 sctp Discard [Randall_Stewart] [Randall_Stewart] 2022-02-07 [RFC9260]
discard 9 dccp Discard [Eddie_Kohler] [Eddie_Kohler] [RFC4340] 1145656131
chargen 19 tcp Character Generator
chargen 19 udp Character Generator
ftp-data 20 sctp FTP [Randall_Stewart] [Randall_Stewart] 2022-02-07 [RFC9260]
ftp 21 tcp File Transfer Protocol [Control] [Jon_Postel] [Jon_Postel] [RFC959] Defined TXT keys: u=<username> p=<password> path=<path>
ftp 21 udp File Transfer Protocol [Control] [Jon_Postel] [Jon_Postel] [RFC959] Defined TXT keys: u=<username> p=<password> path=<path>
ftp 21 sctp FTP [Randall_Stewart] [Randall_Stewart] 2022-02-07 [RFC9260] Defined TXT keys: u=<username> p=<password> path=<path>
ssh 22 sctp SSH [Randall_Stewart] [Randall_Stewart] 2022-02-07 [RFC9260] Defined TXT keys: u=<username> p=<password>
msg-icp 29 tcp MSG ICP [Robert_Thomas] [Robert_Thomas]
msg-icp 29 udp MSG ICP [Robert_Thomas] [Robert_Thomas]
rlp 39 tcp Resource Location Protocol [Mike_Accetta] [Mike_Accetta]
rlp 39 udp Resource Location Protocol [Mike_Accetta] [Mike_Accetta]
tacacs 49 tcp Login Host Protocol (TACACS) [Pieter_Ditmars] [Pieter_Ditmars]
tacacs 49 udp Login Host Protocol (TACACS) [Pieter_Ditmars] [Pieter_Ditmars]
59 tcp any private file service [Jon_Postel] [Jon_Postel]
59 udp any private file service [Jon_Postel] [Jon_Postel]
bootps 67 tcp Bootstrap Protocol Server [Bill_Croft] [Bill_Croft] [RFC951] Defined TXT keys: None
tftp 69 tcp Trivial File Transfer [David_Clark] [David_Clark]
tftp 69 udp Trivial File Transfer [David_Clark] [David_Clark]
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)
http 80 tcp World Wide Web HTTP [IESG] [IETF_Chair] 2021-10-01 [RFC9110] Defined TXT keys: u=<username> p=<password> path=<path to document>
http 80 udp World Wide Web HTTP [IESG] [IETF_Chair] 2021-10-01 [RFC9110] Defined TXT keys: u=<username> p=<password> path=<path to document>
www 80 tcp World Wide Web HTTP [IESG] [IETF_Chair] 2021-10-01 [RFC9110] This is a duplicate of the "http" service and should not be used for discovery purposes.
www 80 udp World Wide Web HTTP [IESG] [IETF_Chair] 2021-10-01 [RFC9110] This is a duplicate of the "http" service and should not be used for discovery purposes.
http 80 sctp HTTP [Randall_Stewart] [Randall_Stewart] 2022-02-07 [RFC9260] Defined TXT keys: u=<username> p=<password> path=<path to document>
su-mit-tg 89 tcp SU/MIT Telnet Gateway [Mark_Crispin] [Mark_Crispin]
su-mit-tg 89 udp SU/MIT Telnet Gateway [Mark_Crispin] [Mark_Crispin]
dnsix 90 tcp DNSIX Securit Attribute Token Map [Charles_Watt] [Charles_Watt] PORT 90 also being used unofficially by Pointcast
dnsix 90 udp DNSIX Securit Attribute Token Map [Charles_Watt] [Charles_Watt] PORT 90 also being used unofficially by Pointcast
mit-dov 91 tcp MIT Dover Spooler [Eliot_Moss] [Eliot_Moss]
mit-dov 91 udp MIT Dover Spooler [Eliot_Moss] [Eliot_Moss]
npp 92 tcp Network Printing Protocol [Louis_Mamakos] [Louis_Mamakos]
npp 92 udp Network Printing Protocol [Louis_Mamakos] [Louis_Mamakos]
dcp 93 tcp Device Control Protocol [Daniel_Tappan] [Daniel_Tappan]
dcp 93 udp Device Control Protocol [Daniel_Tappan] [Daniel_Tappan]
objcall 94 tcp Tivoli Object Dispatcher [Tom_Bereiter] [Tom_Bereiter]
objcall 94 udp Tivoli Object Dispatcher [Tom_Bereiter] [Tom_Bereiter]
supdup 95 tcp SUPDUP [Mark_Crispin] [Mark_Crispin]
supdup 95 udp SUPDUP [Mark_Crispin] [Mark_Crispin]
dixie 96 tcp DIXIE Protocol Specification [Tim_Howes] [Tim_Howes]
dixie 96 udp DIXIE Protocol Specification [Tim_Howes] [Tim_Howes]
swift-rvf 97 tcp Swift Remote Virtural File Protocol [Maurice_R_Turcotte] [Maurice_R_Turcotte]
swift-rvf 97 udp Swift Remote Virtural File Protocol [Maurice_R_Turcotte] [Maurice_R_Turcotte]
tacnews 98 tcp TAC News [Jon_Postel] [Jon_Postel]
tacnews 98 udp TAC News [Jon_Postel] [Jon_Postel]
metagram 99 tcp Metagram Relay [Geoff_Goodfellow] [Geoff_Goodfellow]
metagram 99 udp Metagram Relay [Geoff_Goodfellow] [Geoff_Goodfellow]
pop2 109 tcp Post Office Protocol - Version 2 [Joyce_K_Reynolds] [Joyce_K_Reynolds]
pop2 109 udp Post Office Protocol - Version 2 [Joyce_K_Reynolds] [Joyce_K_Reynolds]
nntp 119 tcp Network News Transfer Protocol [IESG] [IETF_Chair] 2018-07-06 [RFC3977]
nntp 119 udp Network News Transfer Protocol [IESG] [IETF_Chair] 2018-07-06 [RFC3977]
ntp 123 tcp Network Time Protocol [Dave_Mills] [Dave_Mills] [RFC5905]
ntp 123 udp Network Time Protocol [Dave_Mills] [Dave_Mills] [RFC5905]
pwdgen 129 tcp Password Generator Protocol [Frank_J_Wacho] [Frank_J_Wacho]
pwdgen 129 udp Password Generator Protocol [Frank_J_Wacho] [Frank_J_Wacho]
netbios-ssn 139 tcp NETBIOS Session Service [Jon_Postel] [Jon_Postel]
netbios-ssn 139 udp NETBIOS Session Service [Jon_Postel] [Jon_Postel]
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]
nss-routing 159 tcp NSS-Routing [Yakov_Rekhter] [Yakov_Rekhter]
nss-routing 159 udp NSS-Routing [Yakov_Rekhter] [Yakov_Rekhter]
send 169 tcp SEND [William_Oldwin] [William_Oldwin] 2019-04-22
send 169 udp SEND [William_Oldwin] [William_Oldwin] 2019-04-22
bgp 179 tcp Border Gateway Protocol [Kirk_Lougheed] [Kirk_Lougheed]
bgp 179 udp Border Gateway Protocol [Kirk_Lougheed] [Kirk_Lougheed]
bgp 179 sctp BGP [Randall_Stewart] [Randall_Stewart] 2022-02-07 [RFC9260]
qft 189 tcp Queued File Transport [Wayne_Schroeder] [Wayne_Schroeder]
qft 189 udp Queued File Transport [Wayne_Schroeder] [Wayne_Schroeder]
gacp 190 tcp Gateway Access Control Protocol [C_Philip_Wood] [C_Philip_Wood]
gacp 190 udp Gateway Access Control Protocol [C_Philip_Wood] [C_Philip_Wood]
prospero 191 tcp Prospero Directory Service [B_Clifford_Neuman] [B_Clifford_Neuman]
prospero 191 udp Prospero Directory Service [B_Clifford_Neuman] [B_Clifford_Neuman]
osu-nms 192 tcp OSU Network Monitoring System [Doug_Karl] [Doug_Karl]
osu-nms 192 udp OSU Network Monitoring System [Doug_Karl] [Doug_Karl]
srmp 193 tcp Spider Remote Monitoring Protocol [Ted_J_Socolofsky] [Ted_J_Socolofsky]
srmp 193 udp Spider Remote Monitoring Protocol [Ted_J_Socolofsky] [Ted_J_Socolofsky]
irc 194 tcp Internet Relay Chat Protocol [Jarkko_Oikarinen] [Jarkko_Oikarinen]
irc 194 udp Internet Relay Chat Protocol [Jarkko_Oikarinen] [Jarkko_Oikarinen]
dn6-nlm-aud 195 tcp DNSIX Network Level Module Audit
dn6-nlm-aud 195 udp DNSIX Network Level Module Audit
dn6-smm-red 196 tcp DNSIX Session Mgt Module Audit Redir [Lawrence_Lebahn] [Lawrence_Lebahn]
dn6-smm-red 196 udp DNSIX Session Mgt Module Audit Redir [Lawrence_Lebahn] [Lawrence_Lebahn]
dls 197 tcp Directory Location Service
dls 197 udp Directory Location Service
dls-mon 198 tcp Directory Location Service Monitor [Scott_Bellew] [Scott_Bellew]
dls-mon 198 udp Directory Location Service Monitor [Scott_Bellew] [Scott_Bellew]
smux 199 tcp SMUX [Marshall_Rose] [Marshall_Rose]
smux 199 udp SMUX [Marshall_Rose] [Marshall_Rose]
qmtp 209 tcp The Quick Mail Transfer Protocol [D_J_Bernstein] [D_J_Bernstein] 2018-04-05
qmtp 209 udp The Quick Mail Transfer Protocol [D_J_Bernstein] [D_J_Bernstein] 2018-04-05
z39-50 210 tcp ANSI Z39.50

IANA assigned this well-formed service name as a replacement for "z39.50".
[Mark_H_Needleman] [Mark_H_Needleman]
z39.50 210 tcp ANSI Z39.50 [Mark_H_Needleman] [Mark_H_Needleman] This entry is an alias to "z39-50". This entry is now historic, not usable for use with many common service discovery mechanisms.
z39-50 210 udp ANSI Z39.50

IANA assigned this well-formed service name as a replacement for "z39.50".
[Mark_H_Needleman] [Mark_H_Needleman]
z39.50 210 udp ANSI Z39.50 [Mark_H_Needleman] [Mark_H_Needleman] This entry is an alias to "z39-50". This entry is now historic, not usable for use with many common service discovery mechanisms.

Contact Information

ID Name Organization Contact URI Last Updated
[Albert_G_Broscius] Albert G. Broscius mailto:broscius&dsl.cis.upenn.edu
[B_Clifford_Neuman] B. Clifford Neuman mailto:bcn&isi.edu 2022-02-18
[Bill_Croft] Bill Croft mailto:Croft&sumex-aim.stanford.edu
[C_Philip_Wood] C. Philip Wood mailto:cpw&lanl.gov
[Charles_Watt] Charles Watt mailto:watt&sware.com
[D_J_Bernstein] D. J. Bernstein mailto:ports&box.cr.yp.to 2018-04-05
[Daniel_Tappan] Daniel Tappan mailto:Tappan&bbn.com
[Dave_Mills] Dave Mills mailto:mills&udel.edu 2022-06-03
[David_Clark] David Clark mailto:ddc&lcs.mit.edu
[David_Zimmerman] David Zimmerman mailto:dpz&rutgers.edu
[Doug_Karl] Doug Karl mailto:KARL-D&osu-20.ircc.ohio-state.edu
[Eddie_Kohler] Eddie Kohler IETF dccp WG mailto:kohler&cs.ucla.edu
[Eliot_Moss] Eliot Moss mailto:EBM&xx.lcs.mit.edu
[Frank_J_Wacho] Frank J. Wacho mailto:WANCHO&wsmr-simtel20.army.mil
[Geoff_Goodfellow] Geoff Goodfellow mailto:Geoff&fernwood.mpk.ca.us
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Jarkko_Oikarinen] Jarkko Oikarinen mailto:jto&tolsun.oulu.fi
[Jon_Postel] Jon Postel mailto:postel&isi.edu
[Joyce_K_Reynolds] Joyce K. Reynolds mailto:jkrey&isi.edu
[Kirk_Lougheed] Kirk Lougheed mailto:LOUGHEED&mathom.cisco.com
[Lawrence_Lebahn] Lawrence Lebahn mailto:DIA3&paxrv-nes.navy.mil
[Louis_Mamakos] Louis Mamakos mailto:louie&sayshell.umd.edu
[Mark_Crispin] Mark Crispin mailto:MRC&panda.com
[Mark_H_Needleman] Mark H. Needleman mailto:markn&sirsi.com
[Marshall_Rose] Marshall Rose mailto:mrose17&gmail.com 2024-07-29
[Maurice_R_Turcotte] Maurice R. Turcotte mailto:mailrus!uflorida!rm1!dnmrt%25rmatl@uunet.uu.net
[Mike_Accetta] Mike Accetta mailto:MIKE.ACCETTA&cmu-cs-a.edu
[Pieter_Ditmars] Pieter Ditmars mailto:pditmars&bbn.com
[Randall_Stewart] Randall Stewart IETF TSVWG mailto:rrs&lakerest.net
[Robert_Thomas] Robert Thomas mailto:BThomas&f.bbn.com
[Scott_Bellew] Scott Bellew mailto:smb&cs.purdue.edu
[Ted_J_Socolofsky] Ted J. Socolofsky mailto:Teds&spider.co.uk
[Tim_Howes] Tim Howes mailto:Tim.Howes&terminator.cc.umich.edu
[Tom_Bereiter] Tom Bereiter
[Wayne_Schroeder] Wayne Schroeder mailto:schroeder&sds.sdsc.edu
[William_Oldwin] William Oldwin mailto:william&bitsome.ie 2022-01-28
[Yakov_Rekhter] Yakov Rekhter mailto:Yakov&ibm.com