Service Name and Transport Protocol Port Number Registry

Last Updated
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
  [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
aero 8060 udp Asymmetric Extended Route Optimization (AERO) [IESG] [IETF_Chair] [RFC6706]
hncp-udp-port 8231 udp HNCP [IESG] [IETF_Chair] 2016-01-13 [RFC7788]
hncp-dtls-port 8232 udp HNCP over DTLS [IESG] [IETF_Chair] 2016-01-13 [RFC7788]
pim-port 8471 tcp PIM over Reliable Transport [IESG] [IETF_Chair] 2008-08-21 [RFC6559]
pim-port 8471 sctp PIM over Reliable Transport [IESG] [IETF_Chair] 2008-08-21 [RFC6559]
lsp-self-ping 8503 udp MPLS LSP Self-Ping [IESG] [IETF_Chair] 2015-06-11 2016-02-01 [RFC7746]
kca-service 9878 udp The KX509 Kerberized Certificate Issuance Protocol in Use in 2012 [IESG] [IETF_Chair] 2012-07-12 [RFC6717] Historically, this service has been referred to as "kca_service", but this service name does not meet the registry requirements.
sctp-tunneling 9899 udp SCTP TUNNELING [IESG] [IETF_Chair] 2013-04-10 [RFC6951]
hip-nat-t 10500 udp HIP NAT-Traversal [IESG] [IETF_Chair] 2020-08-12 [RFC5770][RFC9028]
mle 19788 udp Mesh Link Establishment [IESG] [IETF_Chair] 2012-12-18
udpstp 24601 udp UDP-based IP-Layer Capacity and Performance Measurement protocol [IESG] [IETF_Chair] 2025-09-26 [RFC-ietf-ippm-capacity-protocol-25]
mtrace 33435 udp IP Multicast Traceroute [IESG] [IETF_Chair] 2017-12-13 2019-08-09 [RFC8487] Known Unauthorized Use on port 33435
brski-proxy tcp The Bootstrapping Remote Secure Key Infrastructure Proxy [IESG] [IETF_Chair] 2020-04-29 [RFC8995] Defined TXT keys: None
brski-reg-cmp tcp Bootstrapping Remote Secure Key Infrastructure registrar with CMP capabilities according to the Lightweight CMP Profile (LCMPP) [RFC9483] [IESG] [IETF_Chair] 2024-09-23 [RFC9733] Defined TXT keys: None
brski-registrar tcp The Bootstrapping Remote Secure Key Infrastructure Registrar [IESG] [IETF_Chair] 2020-04-29 [RFC8995] Defined TXT keys: None
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>
certificates tcp Server for S/MIME and PGP certificates [IESG] [John_Levine] 2016-07-26 [draft-bhjl-x509-srv-01] Defined TXT keys: None
convert tcp 0-RTT TCP Convert Protocol [IESG] [IETF_Chair] 2020-03-27 [RFC8803] Defined TXT keys: None
core-rd tcp Resource Directory accessed using CoAP over TCP [IESG] [IETF_Chair] 2021-03-16 [RFC9176] Defined TXT keys: None
core-rd udp Resource Directory accessed using CoAP [IESG] [IETF_Chair] 2021-03-16 [RFC9176] Defined TXT keys: None
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-push-tls tcp DNS Push Notification Service Type [IESG] [IETF_Chair] 2019-11-25 [RFC8765, Section 6.1] Defined TXT Keys: None
dnssd-srp tcp DNS-Based Service Discovery [IESG] [IETF_Chair] 2024-04-12 2024-09-05 [RFC9665] Defined TXT keys: None
dnssd-srp-tls tcp DNS-Based Service Discovery (TLS) [IESG] [IETF_Chair] 2024-04-12 2024-09-05 [RFC9665] Defined TXT keys: None
dots-call-home tcp DOTS Signal Channel Call Home Protocol. The service name is used to construct the SRV service names "_dots-call-home._udp" and "_dots-call-home._tcp" for discovering Call Home DOTS clients used to establish DOTS signal channel call home. [IESG] [IETF_Chair] 2020-11-19 [RFC8973] Defined TXT keys: None
dots-call-home udp DOTS Signal Channel Call Home Protocol. The service name is used to construct the SRV service names "_dots-call-home._udp" and "_dots-call-home._tcp" for discovering Call Home DOTS clients used to establish DOTS signal channel call home. [IESG] [IETF_Chair] 2020-11-19 [RFC8973] Defined TXT keys: None
dots-data tcp DOTS Data Channel Protocol. The service name is used to construct the SRV service name "_dots-data._tcp" for discovering DOTS servers used to establish DOTS data channel. [IESG] [IETF_Chair] 2020-11-19 [RFC8973] Defined TXT keys: None
jmap tcp JSON Meta Application Protocol [IESG] [IETF_Chair] 2016-01-22 2019-07-16 [RFC8620] This service name was previously assigned under the name "JSON Mail Access Protocol". This has been de-assigned and re-assigned with the approval of the previous assignee.
nfs-domainroot tcp NFS service for the domain root, the root of an organization's published file namespace. [IESG] [IETF_Chair] 2012-04-24 [RFC6641] Defined TXT keys: None
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
smimeca tcp Domain signing certificate for S/MIME keys [IESG] [John_Levine] 2016-07-26 [draft-bhjl-x509-srv-01] Defined TXT keys: None
sztp tcp This service name is used to construct the SRV service label "_sztp" for discovering SZTP bootstrap servers. [IESG] [IETF_Chair] 2019-01-17 [RFC8572] This protocol uses HTTPS as a substrate.
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]).

Contact Information

ID Name Organization Contact URI Last Updated
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[John_Levine] John Levine mailto:standards&taugh.com 2016-07-26