Service Name and Transport Protocol Port Number Registry

Last Updated
2026-09-02
Expert(s)
TCP/UDP: Joe Touch; Eliot Lear, Kumiko Ono, Wes Eddy, Brian Trammell,
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
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
hyperstream Atempo HyperStream deduplication server [Laurent_Charmet] [Laurent_Charmet] Defined TXT keys: version=x.y.z.w uuid=<36 bytes UUID string> host=<real host name>
im tcp Instant Messaging [RFC3861]
im udp Instant Messaging [RFC3861]
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.
jnx-kcsync tcp jollys keychain cloud sync protocol [Patrick_Stein] [Patrick_Stein] 2011-10-24 Defined TXT keys: hash=<40hex characters> salt=<40hex characters> uuid=<40hex characters> Example: hash=5e7580598c0d7064d4fc79faaeb42585e1a675f8 salt=f0164cb3a0c3d7efe75abea8fda86d2d56c8dda9 uuid=db61dc092922252e45bbb264f59147138c7fd5fa
msrps tcp MSRP protocol over TLS 2014-04-25 [RFC4976] Defined TXT keys:
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
pkixrep Public Key Infrastructure Repository Locator Service [RFC4386]
pres tcp Presence [RFC3861]
pres udp Presence [RFC3861]
snif-fifo tcp SNIF End-to-End TLS Relay Cluster [VESvault_Corp] [Jim_Zubov] 2021-12-15 2026-07-22 [draft-zubov-snif-05, Section 4.6] Defined TXT keys: None
split-dns64 tcp DNS64 in split configuration [Kasper_Dupont] [Kasper_Dupont] 2021-10-19 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]).

Contact Information

ID Name Organization Contact URI Last Updated
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Jim_Zubov] Jim Zubov VESvault Corp mailto:jz&vesvault.com 2021-12-29
[Kasper_Dupont] Kasper Dupont mailto:kasperd&xwhfx.16.oct.2021.kasperd.dk 2021-10-19
[Laurent_Charmet] Laurent Charmet mailto:laurent.charmet&atempo.com
[Patrick_Stein] Patrick Stein mailto:Patrick.Stein&jinx.eu 2011-10-24
[VESvault_Corp] VESvault Corp mailto:info&vesvault.com 2021-12-29