Internet Assigned Numbers Authority

Service Name and Transport Protocol Port Number Registry

Last Updated
2025-05-05
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
snmpdtls-trap 10162 udp SNMP-Trap-DTLS [RFC6353]
icpps 14143 tcp IceWall Cert Protocol over TLS [Kenta_Kambara] [Kenta_Kambara] 2016-05-24
onep-tls 15002 tcp Open Network Environment TLS [Cisco_3] [Andrew_Thurber] 2014-01-21
amt-redir-tls 16995 tcp Intel(R) AMT Redirection/TLS [Nimrod_Diamant] [Nimrod_Diamant] 2005-02
amt-redir-tls 16995 udp Intel(R) AMT Redirection/TLS [Nimrod_Diamant] [Nimrod_Diamant] 2005-02
db2c-tls 25100 tcp IBM Db2 Client Interface - Encrypted [IBM] [Matthew_Emmerton] 2024-03-05
z-wave-s 41230 tcp Z-Wave Protocol over SSL/TLS [Sigma_Designs_3] [Anders_Brandt_4] 2015-06-26
z-wave-s 41230 udp Z-Wave Protocol over DTLS [Sigma_Designs_3] [Anders_Brandt_4] 2015-06-26
caldav tcp Calendaring Extensions to WebDAV (CalDAV) - non-TLS [IESG] [IETF_Chair] 2012-02-17 [RFC6764] This is an extension of the http service. Defined TXT keys: path=<context path>
caldavs tcp Calendaring Extensions to WebDAV (CalDAV) - over TLS [IESG] [IETF_Chair] 2012-02-17 [RFC6764] This is an extension of the https service. Defined TXT keys: path=<context path>
carddav tcp vCard Extensions to WebDAV (CardDAV) - non-TLS [IESG] [IETF_Chair] 2012-02-17 [RFC6352] This is an extension of the http service. Defined TXT keys: path=<context path>
carddavs tcp vCard Extensions to WebDAV (CardDAV) - over TLS [IESG] [IETF_Chair] 2012-02-17 [RFC6352] This is an extension of the https service. Defined TXT keys: path=<context path>
core-rd-tls tcp Resource Directory accessed using CoAP over TLS [IESG] [IETF_Chair] 2021-03-16 2022-04-14 [RFC9176] Defined TXT keys: None
core-rd-dtls udp Resource Directory accessed using CoAP over DTLS [IESG] [IETF_Chair] 2021-03-16 [RFC9176] Defined TXT keys: None
dns-llq-tls tcp DNS Long-Lived Queries over TLS [Stuart_Cheshire] [Stuart_Cheshire] 2019-05-04 [RFC6281] Defined TXT Keys: None
dns-push-tls tcp DNS Push Notification Service Type [IESG] [IETF_Chair] 2019-11-25 [RFC8765, Section 6.1] Defined TXT Keys: None
dns-query-tls tcp DNS queries to the authoritative server over TLS [Stuart_Cheshire] [Stuart_Cheshire] 2019-05-04 Defined TXT Keys: None
dns-update-tls tcp DNS Dynamic Update Service over TLS [Stuart_Cheshire] [Stuart_Cheshire] 2019-05-04 [RFC6281] DNS Dynamic Update Service for a given domain may not necessarily be provided by the principal name servers as advertised by the domain's "NS" records, and may not necessarily always be provided on port 53. The "_dns-update._udp.<domain>." SRV record gives the target host and port where DNS Dynamic Update Service is provided for the named domain.
dnssd-srp-tls tcp DNS-Based Service Discovery (TLS) [IESG] [IETF_Chair] 2024-04-12 2024-09-05 [RFC-ietf-dnssd-srp-25] Defined TXT keys: None
https tcp HTTP over SSL/TLS [Tim_Berners_Lee] [Tim_Berners_Lee] Web browsers like Safari and Internet Explorer (with the Bonjour for Windows plugin) DO NOT browse for DNS-SD service type "_https._tcp" in addition to browsing for "_http._tcp". This is a conscious decision to reduce proliferation of service types, to help keep DNS-SD efficient on the network. Today, if a user types http://www.mybank.com/ into their web browser, the web server automatically redirects the user to https://www.mybank.com/. Rather than having an entirely different DNS-SD service type for https, we recommend using the same redirection mechanism: advertise a plain "http" service, which consists of nothing except an HTTP redirection to the desired "https" URL. Work is currently being done on adding mechanisms to HTTP and TLS to allow the server to tell the client that it needs to activate TLS on the current connection before proceeding. If this becomes widely adopted, it further justifies the decision to not create a separate DNS-SD service type "_https._tcp", because security becomes just another one of the things that is negotiated on a per-connection basis (like content-type negotiation today) rather than being an entirely separate thing.
llrp-secure RFID reader Low Level Reader Protocol over SSL/TLS [Jason_Schoon_2] [Jason_Schoon_2] Defined TXT keys: None
msrps tcp MSRP protocol over TLS 2014-04-25 [RFC4976] Defined TXT keys:
radiusdtls udp Authentication, Accounting, and Dynamic Authorization via the RADIUS protocol. This service name is used to construct the SRV service label "_radiusdtls" for discovery of RADIUS/DTLS servers. [IESG] [IETF_Chair] 2015-03-23 2015-10-06 [RFC7585] Defined TXT keys: None
radiustls tcp Authentication, Accounting, and Dynamic Authorization via the RADIUS protocol. This service name is used to construct the SRV service label "_radiustls" for discovery of RADIUS/TLS servers. [IESG] [IETF_Chair] 2015-03-23 2015-10-06 [RFC7585] Defined TXT keys: None
snif-cln tcp End-to-end TLS Relay Client Connection [VESvault_Corp] [Jim_Zubov] 2021-12-15 [https://snif.host/relay-proto#snif-cln] Defined TXT keys: None
snif-fifo tcp End-to-end TLS Relay Cluster [VESvault_Corp] [Jim_Zubov] 2021-12-15 [https://snif.host/relay-proto#snif-fifo] Defined TXT keys: None
snif-srv tcp End-to-end TLS Relay Service Connection [VESvault_Corp] [Jim_Zubov] 2021-12-29 [https://snif.host/relay-proto#snif-srv] 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]).
webdavs WebDAV over SSL/TLS [Y_Y_Goland] [Y_Y_Goland] Defined TXT keys: u=<username> p=<password> path=<path>
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
[Anders_Brandt_4] Anders Brandt Sigma Designs mailto:anders_brandt&sigmadesigns.com 2015-06-26
[Andrew_Thurber] Andrew Thurber Cisco mailto:anthurbe@cisco.com> 2014-01-21
[Cisco_3] Cisco mailto:anthurbe@cisco.com> 2014-01-21
[IBM] IBM mailto:memmerto&ca.ibm.com 2024-03-05
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Jason_Schoon_2] Jason Schoon mailto:jason.schoon&intermec.com
[Jim_Zubov] Jim Zubov VESvault Corp mailto:jz&vesvault.com 2021-12-29
[Kazuyuki_Ashimura] Kazuyuki Ashimura mailto:ashimura&w3.org 2022-11-22
[Kenta_Kambara] Kenta Kambara mailto:kenta.kambara&hpe.com 2016-05-24
[Matthew_Emmerton] Matthew Emmerton IBM mailto:memmerto&ca.ibm.com 2024-03-05
[Nimrod_Diamant] Nimrod Diamant mailto:nimrod.diamant&intel.com 2005-02
[Sigma_Designs_3] Sigma Designs mailto:anders_brandt&sigmadesigns.com 2015-06-26
[Stuart_Cheshire] Stuart Cheshire mailto:cheshire&apple.com 2022-07-11
[Tim_Berners_Lee] Tim Berners-Lee mailto:timbl&w3.org
[VESvault_Corp] VESvault Corp mailto:info&vesvault.com 2021-12-29
[W3C_Web_of_Things_Working_Group] W3C Web of Things Working Group mailto:team-wot&w3.org 2022-11-22
[Y_Y_Goland] Y. Y. Goland mailto:yarong&microsoft.com