Internet Assigned Numbers Authority

Service Name and Transport Protocol Port Number Registry

Last Updated
2025-08-07
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
pgpkey-mailto PGP Key submission using SMTP [Jeroen_Massar_3] [Jeroen_Massar_3] Defined TXT keys: user=<user portion of the mail address>
pkixrep Public Key Infrastructure Repository Locator Service [RFC4386]
pres tcp Presence [RFC3861]
pres udp Presence [RFC3861]
rgb tcp RGB Spectrum Device Discovery [RGB_Spectrum] [Steve_Hershey] 2011-10-10 Defined TXT keys: Keyboard, Mouse, Option1, Option2, Option3, Option4, ModelName
robustirc tcp Like ircu (RFC1459), but failure tolerant due to strong consistency among n>=3 servers [Michael_Stapelberg] [Michael_Stapelberg] 2015-01-07 Defined TXT keys: None
rsmp-server Remote System Management Protocol (Server Instance) [Geoff_Back_3] [Geoff_Back_3] Defined TXT keys: apiver=<major.minor>
scpi-raw IEEE 488.2 (SCPI) Socket [Nick_Barendt_3] [Nick_Barendt_3] Defined TXT keys: None
scpi-telnet IEEE 488.2 (SCPI) Telnet [Nick_Barendt_3] [Nick_Barendt_3] Defined TXT keys: None
sessionfs Session File Sharing [Anthony_Williams] [Anthony_Williams] Defined TXT keys: Text keys are the file extensions of any file the user plans to share, i.e. pdf, doc, mp3.
slimcli SliMP3 Server Command-Line Interface [Dean_Blackketter_2] [Dean_Blackketter_2] Defined TXT keys: None
slimhttp SliMP3 Server Web Interface [Dean_Blackketter_2] [Dean_Blackketter_2] Defined TXT keys: None
slpda tcp Remote Service Discovery in the Service Location [RFC3832]
slpda udp Remote Service Discovery in the Service Location [RFC3832]
strobe-sync tcp Strobe Synchronization [Jasper_Morgal] [Richard_Morgal] 2019-06-13 Defined TXT keys: Application will rely upon Bonjour version 3.1.0.1
surveillus Surveillus Networks Discovery Protocol [Mark_Lewis_3] [Mark_Lewis_3] Defined TXT keys: None
timezone tcp Time Zone Data Distribution Service - non-TLS [IESG] [IETF_Chair] 2015-08-03 [RFC7808] This is an extension of the http service. Defined TXT keys: path=<context path> (as per Section 6 of [RFC6763]).
timezones tcp Time Zone Data Distribution Service - over TLS [IESG] [IETF_Chair] 2015-08-03 [RFC7808] This is an extension of the https service. Defined TXT keys: path=<context path> (as per Section 6 of [RFC6763]).
touch-able iPhone and iPod touch Remote Controllable [Amandeep_Jawa_3] [Amandeep_Jawa_3] Defined TXT keys: txtvers, CtlN, DbId, Ver, DvTy, OSsi, DvSv
touch-remote iPhone and iPod touch Remote Pairing [Amandeep_Jawa_3] [Amandeep_Jawa_3] Defined TXT keys: txtvers, DvNm, Pair, RemV, RemN, DvTy
voalte3 tcp Server location via DNS-SD [Voalte_Inc] [John_Simpson] 2019-01-22 Defined TXT keys: txtvers, name, (others not publicly documented)
wot tcp W3C WoT Thing Description or Directory [W3C_Web_of_Things_Working_Group] [Kazuyuki_Ashimura] 2022-11-22 2022-12-15

Defined TXT keys:

td: Absolute pathname of the Thing Description of the Thing or Thing Description of the Thing Description Directory.

type: Type of the Thing Description, i.e. "Thing" or "Directory". If omitted, the type is assumed to be Thing.

scheme: Scheme part of URL. One of the following values can be specified, with the standard registered URI interpretations [RFC7595]: http (HTTP over TCP),https (HTTP over TLS/TCP), coap+tcp (CoAP over TCP), or coaps+tcp (CoAP over TLS/TCP). If omitted, the scheme is assumed to be http.

wot udp W3C WoT Thing Description or Directory [W3C_Web_of_Things_Working_Group] [Kazuyuki_Ashimura] 2022-11-22 2022-12-15

Defined TXT keys:

td: Absolute pathname of the Thing Description of the Thing or Thing Description of the Thing Description Directory.

type: Type of the Thing Description, i.e. "Thing" or "Directory". If omitted, the type is assumed to be Thing.

scheme: Scheme part of URL. One of the following values can be specified, with the standard registered URI interpretations [RFC7595]: coap (CoAP over UDP), coaps CoAP over DTLS/UDP. If omitted, the scheme is assumed to be coap.

Contact Information

ID Name Organization Contact URI Last Updated
[Amandeep_Jawa_3] Amandeep Jawa mailto:daap&apple.com
[Anthony_Williams] Anthony Williams mailto:tonydubs&gmail.com
[Dean_Blackketter_2] Dean Blackketter mailto:dean&slimdevices.com
[Geoff_Back_3] Geoff Back mailto:geoff&demonlair.co.uk
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Jasper_Morgal] Jasper Morgal mailto:jpmorgal8&gmail.com 2019-06-13
[Jeroen_Massar_3] Jeroen Massar mailto:jeroen&unfix.org
[John_Simpson] John Simpson Voalte, Inc. mailto:jms1&voalte.com 2019-01-22
[Kazuyuki_Ashimura] Kazuyuki Ashimura mailto:ashimura&w3.org 2022-11-22
[Mark_Lewis_3] Mark Lewis mailto:mark&surveillus.com
[Michael_Stapelberg] Michael Stapelberg mailto:michael+iana&stapelberg.ch 2015-01-07
[Nick_Barendt_3] Nick Barendt mailto:nbarendt&vxitech.com
[RGB_Spectrum] RGB Spectrum mailto:shershey&rgb.com 2011-10-10
[Richard_Morgal] Richard Morgal mailto:rmorgal&wildblue.net 2019-06-13
[Steve_Hershey] Steve Hershey RGB Spectrum mailto:shershey&rgb.com 2011-10-10
[Voalte_Inc] Voalte, Inc. mailto:engops&voalte.com 2019-01-22
[W3C_Web_of_Things_Working_Group] W3C Web of Things Working Group mailto:team-wot&w3.org 2022-11-22