Service Name and Transport Protocol Port Number Registry
- Last Updated
- 2025-12-15
- 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]
- Available Formats
-

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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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| domain-s | 853 | udp | DNS query-response protocol run over DTLS or QUIC | [IESG] | [IETF_Chair] | 2015-10-08 | 2022-04-01 | [RFC7858][RFC8094][RFC9250] | |||
| dns-llq | 5352 | udp | DNS Long-Lived Queries | [Stuart_Cheshire] | [Stuart_Cheshire] | 2005-08 | 2019-08-26 | [RFC8764] | |||
| mdns | 5353 | udp | Multicast DNS | [IESG] | [IETF_Chair] | [RFC6762] | |||||
| mdnsresponder | 5354 | udp | Multicast DNS Responder IPC | [Stuart_Cheshire_3] | [Stuart_Cheshire_3] | 2004-06 | |||||
| dns-update | tcp | DNS Dynamic Update Service | [Stuart_Cheshire] | [Stuart_Cheshire] | 2019-05-04 | 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. | |||||
| dns-update | udp | DNS Dynamic Update Service | [Stuart_Cheshire] | [Stuart_Cheshire] | 2019-05-04 | 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. | |||||
| 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. |
Contact Information
| ID | Name | Organization | Contact URI | Last Updated |
|---|---|---|---|---|
| [IESG] | IESG | mailto:iesg&ietf.org | ||
| [IETF_Chair] | IETF Chair | IETF | mailto:chair&ietf.org | |
| [Stuart_Cheshire] | Stuart Cheshire | mailto:cheshire&apple.com | 2022-07-11 | |
| [Stuart_Cheshire_3] | Stuart Cheshire | mailto:mdnsresponder-ipc&multicastdns.org | 2004-06 |