Service Name and Transport Protocol Port Number Registry

Last Updated
2026-08-11
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
dhcpv6-client 546 tcp DHCPv6 Client
dhcpv6-client 546 udp DHCPv6 Client [IESG] [IETF_Chair] 2018-05-21 [RFC9915]
dhcpv6-server 547 tcp DHCPv6 Server [IESG] [IETF_Chair] 2018-05-21 [RFC5460]
dhcpv6-server 547 udp DHCPv6 Server [IESG] [IETF_Chair] 2018-05-21 [RFC9915]
dhcp-failover 647 tcp DHCP Failover [IESG] [IETF_Chair] 2018-05-21 [RFC8156]
dhcp-failover 647 udp DHCP Failover [Bernard_Volz] [Bernard_Volz]
dhcp-failover2 847 tcp dhcp-failover 2 [Bernard_Volz] [Bernard_Volz]
dhcp-failover2 847 udp dhcp-failover 2 [Bernard_Volz] [Bernard_Volz]
qip-qdhcp 2490 tcp qip_qdhcp [Mike_Morgan] [Mike_Morgan]
qip-qdhcp 2490 udp qip_qdhcp [Mike_Morgan] [Mike_Morgan]
edcp udp LaCie Ethernet Disk Configuration Protocol [Nicolas_Bouilleaud] [Nicolas_Bouilleaud] Defined TXT keys: ip, mac, dhcp, mask, gtwy, wins, name, version

Contact Information

ID Name Organization Contact URI Last Updated
[Bernard_Volz] Bernard Volz mailto:bevolz&gmail.com 2022-08-03
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Mike_Morgan] Mike Morgan mailto:mmorgan&lucent.com
[Nicolas_Bouilleaud] Nicolas Bouilleaud mailto:nbouilleaud&lacie.com