Internet Assigned Numbers Authority

Service Name and Transport Protocol Port Number Registry

Last Updated
2024-10-15
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
0 tcp Reserved [Jon_Postel] [Jon_Postel]
0 udp Reserved [Jon_Postel] [Jon_Postel]
tcpmux 1 tcp TCP Port Service Multiplexer [Mark_Lottor] [Mark_Lottor]
tcpmux 1 udp TCP Port Service Multiplexer [Mark_Lottor] [Mark_Lottor]
compressnet 2 tcp Management Utility
compressnet 2 udp Management Utility
compressnet 3 tcp Compression Process [Bernie_Volz] [Bernie_Volz]
compressnet 3 udp Compression Process [Bernie_Volz] [Bernie_Volz]
4 tcp Unassigned
4 udp Unassigned
rje 5 tcp Remote Job Entry [Jon_Postel] [Jon_Postel]
rje 5 udp Remote Job Entry [Jon_Postel] [Jon_Postel]
6 tcp Unassigned
6 udp Unassigned
echo 7 tcp Echo [Jon_Postel] [Jon_Postel]
echo 7 udp Echo [Jon_Postel] [Jon_Postel]
8 tcp Unassigned
8 udp Unassigned
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
10 tcp Unassigned
10 udp Unassigned
systat 11 tcp Active Users [Jon_Postel] [Jon_Postel]
systat 11 udp Active Users [Jon_Postel] [Jon_Postel]
12 tcp Unassigned
12 udp Unassigned
daytime 13 tcp Daytime [Jon_Postel] [Jon_Postel] [RFC867]
daytime 13 udp Daytime [Jon_Postel] [Jon_Postel] [RFC867]
14 tcp Unassigned
14 udp Unassigned
15 tcp Unassigned [was netstat]
15 udp Unassigned
16 tcp Unassigned
16 udp Unassigned
qotd 17 tcp Quote of the Day [Jon_Postel] [Jon_Postel]
qotd 17 udp Quote of the Day [Jon_Postel] [Jon_Postel]
msp 18 tcp Message Send Protocol (historic) [Rina_Nethaniel] [Rina_Nethaniel]
msp 18 udp Message Send Protocol (historic) [Rina_Nethaniel] [Rina_Nethaniel]
chargen 19 tcp Character Generator
chargen 19 udp Character Generator
ftp-data 20 tcp File Transfer [Default Data] [Jon_Postel] [Jon_Postel]
ftp-data 20 udp File Transfer [Default Data] [Jon_Postel] [Jon_Postel]
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 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>
ssh 22 sctp SSH [Randall_Stewart] [Randall_Stewart] 2022-02-07 [RFC9260] 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]
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]
26 tcp Unassigned
26 udp Unassigned
nsw-fe 27 tcp NSW User System FE [Robert_Thomas] [Robert_Thomas]
nsw-fe 27 udp NSW User System FE [Robert_Thomas] [Robert_Thomas]
28 tcp Unassigned
28 udp Unassigned
msg-icp 29 tcp MSG ICP [Robert_Thomas] [Robert_Thomas]
msg-icp 29 udp MSG ICP [Robert_Thomas] [Robert_Thomas]
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]
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]

Contact Information

ID Name Organization Contact URI Last Updated
[Bernie_Volz] Bernie Volz mailto:volz&cisco.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
[Jon_Postel] Jon Postel mailto:postel&isi.edu
[Mark_Lottor] Mark Lottor mailto:MKL&nisc.sri.com
[Mike_Accetta] Mike Accetta mailto:MIKE.ACCETTA&cmu-cs-a.edu
[Randall_Stewart] Randall Stewart IETF TSVWG mailto:rrs&lakerest.net
[Rick_Adams] Rick Adams mailto:rick&uunet.uu.net
[Rina_Nethaniel] Rina Nethaniel
[Robert_Thomas] Robert Thomas mailto:BThomas&f.bbn.com
[Robert_Ullmann] Robert Ullmann mailto:ariel&world.std.com