Service Name and Transport Protocol Port Number Registry

Last Updated
2026-08-17
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
tacacss 300 tcp TLS Secure Login Host Protocol (TACACSS) [IESG] [IETF_Chair] 2025-07-15 [RFC9887]
iclcnet-svinfo 887 tcp ICL coNETion server info

IANA assigned this well-formed service name as a replacement for "iclcnet_svinfo".
[Bob_Lyon] [Bob_Lyon]
iclcnet_svinfo 887 tcp ICL coNETion server info [Bob_Lyon] [Bob_Lyon] This entry is an alias to "iclcnet-svinfo". This entry is now historic, not usable for use with many common service discovery mechanisms.
iclcnet-svinfo 887 udp ICL coNETion server info

IANA assigned this well-formed service name as a replacement for "iclcnet_svinfo".
[Bob_Lyon] [Bob_Lyon]
iclcnet_svinfo 887 udp ICL coNETion server info [Bob_Lyon] [Bob_Lyon] This entry is an alias to "iclcnet-svinfo". This entry is now historic, not usable for use with many common service discovery mechanisms.
mtqp 1038 tcp Message Tracking Query Protocol [RFC3887]
mtqp 1038 udp Message Tracking Query Protocol [RFC3887]
filex-lport 1887 tcp FileX Listening Port [Megan_Woods] [Megan_Woods]
filex-lport 1887 udp FileX Listening Port [Megan_Woods] [Megan_Woods]
aironetddp 2887 tcp aironet [Victor_Griswold] [Victor_Griswold]
aironetddp 2887 udp aironet [Victor_Griswold] [Victor_Griswold]
ciphire-data 3887 tcp Ciphire Data Transport [Lars_Eilebrecht] [Lars_Eilebrecht] 2003-10
ciphire-data 3887 udp Ciphire Data Transport [Lars_Eilebrecht] [Lars_Eilebrecht] 2003-10
4886-4887 Unassigned
pcp-multicast 5350 udp Port Control Protocol Multicast [IESG] [IETF_Chair] [RFC6887]
pcp 5351 udp Port Control Protocol [IESG] [IETF_Chair] [RFC6887]
6869-6887 Unassigned
ubroker 7887 tcp Universal Broker [Nathan_Hammond] [Nathan_Hammond] 2005-10
ubroker 7887 udp Universal Broker [Nathan_Hammond] [Nathan_Hammond] 2005-10
8810-8872 Unassigned
dxspider 8873 tcp dxspider linking protocol [Dirk_Koopman] [Dirk_Koopman] 2005-08
dxspider 8873 udp dxspider linking protocol [Dirk_Koopman] [Dirk_Koopman] 2005-08
8874-8879 Unassigned
8884-8887 Unassigned
9879-9887 Unassigned
18882-18887 Unassigned
44323 udp Unassigned "pcp" assignment withdrawn, moved to port 5351 per RFC6887

Contact Information

ID Name Organization Contact URI Last Updated
[Bob_Lyon] Bob Lyon mailto:bl&oasis.icl.co.uk
[Dirk_Koopman] Dirk Koopman mailto:djk&tobit.co.uk 2005-08
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Lars_Eilebrecht] Lars Eilebrecht mailto:le+iana&leogic.com 2003-10
[Megan_Woods] Megan Woods mailto:megan.woods&woods-gebler.com 2024-08-29
[Nathan_Hammond] Nathan Hammond mailto:nathan.hammond&stonebranch.com 2005-10
[Victor_Griswold] Victor Griswold mailto:vgris&aironet.com