Service Name and Transport Protocol Port Number Registry
Service Name and Transport Protocol Port Number Registry
2026-04-09
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
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...
146
Service Name
Port Number
Transport Protocol
Description
Assignee
Contact
Registration Date
Modification Date
Reference
Service Code
Unauthorized Use Reported
Assignment Notes
tcp
Reserved
2024-12-20
RFC6335
udp
Reserved
2024-12-20
RFC6335
tcpmux
tcp
TCP Port Service Multiplexer
Mark_Lottor
Mark_Lottor
tcpmux
udp
TCP Port Service Multiplexer
Mark_Lottor
Mark_Lottor
tcp
Reserved
2025-02-13
De-assigned on 2025-02-13, previously compressnet by [
Bernie_Volz
udp
Reserved
2025-02-13
De-assigned on 2025-02-13, previously compressnet by [
Bernie_Volz
tcp
Reserved
2025-02-13
De-assigned on 2025-02-13, previously compressnet by [
Bernie_Volz
udp
Reserved
2025-02-13
De-assigned on 2025-02-13, previously compressnet by [
Bernie_Volz
tcp
Unassigned
udp
Unassigned
rje
tcp
Remote Job Entry
Jon_Postel
Jon_Postel
rje
udp
Remote Job Entry
Jon_Postel
Jon_Postel
tcp
Unassigned
udp
Unassigned
echo
tcp
Echo
Jon_Postel
Jon_Postel
echo
udp
Echo
Jon_Postel
Jon_Postel
tcp
Unassigned
udp
Unassigned
discard
tcp
Discard
Jon_Postel
Jon_Postel
discard
udp
Discard
Jon_Postel
Jon_Postel
discard
sctp
Discard
Randall_Stewart
Randall_Stewart
2022-02-07
RFC9260
discard
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=
ftp
21
udp
File Transfer Protocol [Control]
Jon_Postel
Jon_Postel
RFC959
Defined TXT keys: u=
ftp
21
sctp
FTP
Randall_Stewart
Randall_Stewart
2022-02-07
RFC9260
Defined TXT keys: u=
ssh
22
tcp
The Secure Shell (SSH) Protocol
RFC4251
Defined TXT keys: u=
ssh
22
udp
The Secure Shell (SSH) Protocol
RFC4251
Defined TXT keys: u=
ssh
22
sctp
SSH
Randall_Stewart
Randall_Stewart
2022-02-07
RFC9260
Defined TXT keys: u=
telnet
23
tcp
Telnet
Jon_Postel
Jon_Postel
RFC854
Defined TXT keys: u=
telnet
23
udp
Telnet
Jon_Postel
Jon_Postel
RFC854
Defined TXT keys: u=
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
RFC-ietf-emailcore-rfc5321bis-43
smtp
25
udp
Simple Mail Transfer
IESG
IETF_Chair
2017-06-05
RFC-ietf-emailcore-rfc5321bis-43
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
...
146
Contact Information
ID
Name
Organization
Contact URI
[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