Internet Assigned Numbers Authority

Service Name and Transport Protocol Port Number Registry

Last Updated
2024-04-19
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
compressnet 3 tcp Compression Process [Bernie_Volz] [Bernie_Volz]
compressnet 3 udp Compression Process [Bernie_Volz] [Bernie_Volz]
discard 9 dccp Discard [Eddie_Kohler] [Eddie_Kohler] [RFC4340] 1145656131
daytime 13 tcp Daytime [Jon_Postel] [Jon_Postel] [RFC867]
daytime 13 udp Daytime [Jon_Postel] [Jon_Postel] [RFC867]
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>
smtp 25 tcp Simple Mail Transfer [IESG] [IETF_Chair] 2017-06-05 [RFC5321]
smtp 25 udp Simple Mail Transfer [IESG] [IETF_Chair] 2017-06-05 [RFC5321]
30 tcp Unassigned
30 udp Unassigned
msg-auth 31 tcp MSG Authentication [Robert_Thomas] [Robert_Thomas]
msg-auth 31 udp MSG Authentication [Robert_Thomas] [Robert_Thomas]
32 tcp Unassigned
32 udp Unassigned
dsp 33 tcp Display Support Protocol [Ed_Cain] [Ed_Cain]
dsp 33 udp Display Support Protocol [Ed_Cain] [Ed_Cain]
34 tcp Unassigned
34 udp Unassigned
35 tcp any private printer server [Jon_Postel] [Jon_Postel]
35 udp any private printer server [Jon_Postel] [Jon_Postel]
36 tcp Unassigned
36 udp Unassigned
time 37 tcp Time [Jon_Postel] [Jon_Postel]
time 37 udp Time [Jon_Postel] [Jon_Postel]
rap 38 tcp Route Access Protocol [Robert_Ullmann] [Robert_Ullmann]
rap 38 udp Route Access Protocol [Robert_Ullmann] [Robert_Ullmann]
rlp 39 tcp Resource Location Protocol [Mike_Accetta] [Mike_Accetta]
rlp 39 udp Resource Location Protocol [Mike_Accetta] [Mike_Accetta]
nicname 43 tcp Who Is
nicname 43 udp Who Is
51 Reserved 2013-05-24 This entry is being removed on 2013-05-24.
domain 53 tcp Domain Name Server [Paul_Mockapetris] [Paul_Mockapetris]
domain 53 udp Domain Name Server [Paul_Mockapetris] [Paul_Mockapetris]
whoispp 63 tcp whois++

IANA assigned this well-formed service name as a replacement for "whois++".
[Rickard_Schoultz] [Rickard_Schoultz]
whois++ 63 tcp whois++ [Rickard_Schoultz] [Rickard_Schoultz] This entry is an alias to "whoispp". This entry is now historic, not usable for use with many common service discovery mechanisms.
whoispp 63 udp whois++

IANA assigned this well-formed service name as a replacement for "whois++".
[Rickard_Schoultz] [Rickard_Schoultz]
whois++ 63 udp whois++ [Rickard_Schoultz] [Rickard_Schoultz] This entry is an alias to "whoispp". This entry is now historic, not usable for use with many common service discovery mechanisms.
netrjs-3 73 tcp Remote Job Service
netrjs-3 73 udp Remote Job Service
mit-ml-dev 83 tcp MIT ML Device [David_Reed] [David_Reed]
mit-ml-dev 83 udp MIT ML Device [David_Reed] [David_Reed]
dcp 93 tcp Device Control Protocol [Daniel_Tappan] [Daniel_Tappan]
dcp 93 udp Device Control Protocol [Daniel_Tappan] [Daniel_Tappan]
gppitnp 103 tcp Genesis Point-to-Point Trans Net
gppitnp 103 udp Genesis Point-to-Point Trans Net
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]
3com-tsmux 106 tcp 3COM-TSMUX [Jeremy_Siegel] [Jeremy_Siegel] Known Unauthorized Use on 106
3com-tsmux 106 udp 3COM-TSMUX [Jeremy_Siegel] [Jeremy_Siegel] Known Unauthorized Use on 106
pop3 110 tcp Post Office Protocol - Version 3 [Marshall_Rose] [Marshall_Rose]
pop3 110 udp Post Office Protocol - Version 3 [Marshall_Rose] [Marshall_Rose]
ident 113 tcp
auth 113 tcp Authentication Service [Mike_St_Johns] [Mike_St_Johns]
auth 113 udp Authentication Service [Mike_St_Johns] [Mike_St_Johns]
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]
cisco-fna 130 tcp cisco FNATIVE
cisco-fna 130 udp cisco FNATIVE
cisco-tna 131 tcp cisco TNATIVE
cisco-tna 131 udp cisco TNATIVE
cisco-sys 132 tcp cisco SYSMAINT
cisco-sys 132 udp cisco SYSMAINT
statsrv 133 tcp Statistics Service [Dave_Mills_2] [Dave_Mills_2]
statsrv 133 udp Statistics Service [Dave_Mills_2] [Dave_Mills_2]
ingres-net 134 tcp INGRES-NET Service [Mike_Berrow] [Mike_Berrow]
ingres-net 134 udp INGRES-NET Service [Mike_Berrow] [Mike_Berrow]
epmap 135 tcp DCE endpoint resolution [Joe_Pato] [Joe_Pato]
epmap 135 udp DCE endpoint resolution [Joe_Pato] [Joe_Pato]
profile 136 tcp PROFILE Naming System [Larry_Peterson] [Larry_Peterson]
profile 136 udp PROFILE Naming System [Larry_Peterson] [Larry_Peterson]
netbios-ns 137 tcp NETBIOS Name Service
netbios-ns 137 udp NETBIOS Name Service
netbios-dgm 138 tcp NETBIOS Datagram Service
netbios-dgm 138 udp NETBIOS Datagram Service
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]
sgmp 153 tcp SGMP [Marty_Schoffstahl] [Marty_Schoffstahl]
sgmp 153 udp SGMP [Marty_Schoffstahl] [Marty_Schoffstahl]
cmip-man 163 tcp CMIP/TCP Manager
cmip-man 163 udp CMIP/TCP Manager
xyplex-mux 173 tcp Xyplex [Bob_Stewart] [Bob_Stewart]
xyplex-mux 173 udp Xyplex [Bob_Stewart] [Bob_Stewart]
ocbinder 183 tcp OCBinder
ocbinder 183 udp OCBinder
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]
at-3 203 tcp AppleTalk Unused
at-3 203 udp AppleTalk Unused
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.
ipx 213 tcp IPX [Don_Provan] [Don_Provan]
ipx 213 udp IPX [Don_Provan] [Don_Provan]
imap3 220 tcp Interactive Mail Access Protocol v3 [James_Rice] [James_Rice]

Contact Information

ID Name Organization Contact URI Last Updated
[Bernie_Volz] Bernie Volz mailto:volz&cisco.com
[Bob_Stewart] Bob Stewart mailto:STEWART&xyplex.com
[Daniel_Tappan] Daniel Tappan mailto:Tappan&bbn.com
[Dave_Mills] Dave Mills mailto:mills&udel.edu 2022-06-03
[Dave_Mills_2] Dave Mills mailto:Mills&huey.udel.edu
[David_Reed] David Reed
[Don_Provan] Don Provan mailto:donp&xlnvax.novell.com
[Ed_Cain] Ed Cain mailto:cain&edn-unix.dca.mil
[Eddie_Kohler] Eddie Kohler IETF dccp WG mailto:kohler&cs.ucla.edu
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[James_Rice] James Rice mailto:RICE&sumex-aim.stanford.edu
[Jeremy_Siegel] Jeremy Siegel mailto:jzs&nsd.3com.com
[Joe_Pato] Joe Pato mailto:pato&apollo.hp.com
[Jon_Postel] Jon Postel mailto:postel&isi.edu
[Larry_Peterson] Larry Peterson mailto:llp&arizona.edu
[Mark_H_Needleman] Mark H. Needleman mailto:markn&sirsi.com
[Marshall_Rose] Marshall Rose mailto:mrose&dbc.mtview.ca.us
[Marty_Schoffstahl] Marty Schoffstahl mailto:schoff&nisc.nyser.net
[Mike_Accetta] Mike Accetta mailto:MIKE.ACCETTA&cmu-cs-a.edu
[Mike_Berrow] Mike Berrow
[Mike_St_Johns] Mike St. Johns mailto:stjohns&arpa.mil
[Patrick_McNamee] Patrick McNamee
[Paul_Mockapetris] Paul Mockapetris mailto:PVM&isi.edu
[Rickard_Schoultz] Rickard Schoultz mailto:schoultz&sunet.se
[Robert_Thomas] Robert Thomas mailto:BThomas&f.bbn.com
[Robert_Ullmann] Robert Ullmann mailto:ariel&world.std.com
[Ted_J_Socolofsky] Ted J. Socolofsky mailto:Teds&spider.co.uk