Internet Assigned Numbers Authority

Service Name and Transport Protocol Port Number Registry

Last Updated
2025-07-22
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
270 tcp Reserved
gist 270 udp Q-mode encapsulation for GIST messages [RFC5971]
pt-tls 271 tcp IETF Network Endpoint Assessment (NEA) Posture Transport Protocol over TLS (PT-TLS) [IESG] [IETF_Chair] 2012-07-31 [RFC6876]
271 udp Reserved
272-279 Unassigned
k-block 287 tcp K-BLOCK [Simon_P_Jackson] [Simon_P_Jackson]
k-block 287 udp K-BLOCK [Simon_P_Jackson] [Simon_P_Jackson]
301-307 Unassigned
zannet 317 tcp Zannet [Zan_Oliphant] [Zan_Oliphant]
zannet 317 udp Zannet [Zan_Oliphant] [Zan_Oliphant]
fatserv 347 tcp Fatmen Server
fatserv 347 udp Fatmen Server
bhoetty 351 tcp bhoetty [John_Kelly] [John_Kelly] This entry records an unassigned but widespread use (added 5/21/97)
bhoetty 351 udp bhoetty [John_Kelly] [John_Kelly] This entry records an unassigned but widespread use (added 5/21/97)
bhoedap4 352 tcp bhoedap4 [John_Kelly] [John_Kelly] This entry records an unassigned but widespread use (added 5/21/97)
bhoedap4 352 udp bhoedap4 [John_Kelly] [John_Kelly] This entry records an unassigned but widespread use (added 5/21/97)
bhevent 357 tcp bhevent [John_Kelly] [John_Kelly]
bhevent 357 udp bhevent [John_Kelly] [John_Kelly]
mortgageware 367 tcp MortgageWare [Ole_Hellevik] [Ole_Hellevik]
mortgageware 367 udp MortgageWare [Ole_Hellevik] [Ole_Hellevik]
codaauth2 370 tcp codaauth2 [Robert_Watson] [Robert_Watson]
codaauth2 370 udp codaauth2 [Robert_Watson] [Robert_Watson]
clearcase 371 tcp Clearcase [Dave_LeBlang] [Dave_LeBlang]
clearcase 371 udp Clearcase [Dave_LeBlang] [Dave_LeBlang]
ulistproc 372 tcp ListProcessor [Anastasios_Kotsikona] [Anastasios_Kotsikona]
ulistproc 372 udp ListProcessor [Anastasios_Kotsikona] [Anastasios_Kotsikona]
legent-1 373 tcp Legent Corporation
legent-1 373 udp Legent Corporation
legent-2 374 tcp Legent Corporation [Keith_Boyce] [Keith_Boyce]
legent-2 374 udp Legent Corporation [Keith_Boyce] [Keith_Boyce]
hassle 375 tcp Hassle [Reinhard_Doelz] [Reinhard_Doelz]
hassle 375 udp Hassle [Reinhard_Doelz] [Reinhard_Doelz]
nip 376 tcp Amiga Envoy Network Inquiry Protocol [Heinz_Wrobel] [Heinz_Wrobel] 2020-10-02
nip 376 udp Amiga Envoy Network Inquiry Protocol [Heinz_Wrobel] [Heinz_Wrobel] 2020-10-02
tnETOS 377 tcp NEC Corporation
tnETOS 377 udp NEC Corporation
dsETOS 378 tcp NEC Corporation [Tomoo_Fujita] [Tomoo_Fujita]
dsETOS 378 udp NEC Corporation [Tomoo_Fujita] [Tomoo_Fujita]
is99c 379 tcp TIA/EIA/IS-99 modem client
is99c 379 udp TIA/EIA/IS-99 modem client
aurp 387 tcp Appletalk Update-Based Routing Pro. [Chris_Ranch] [Chris_Ranch]
aurp 387 udp Appletalk Update-Based Routing Pro. [Chris_Ranch] [Chris_Ranch]
mptn 397 tcp Multi Protocol Trans. Net. [Soumitra_Sarkar] [Soumitra_Sarkar]
mptn 397 udp Multi Protocol Trans. Net. [Soumitra_Sarkar] [Soumitra_Sarkar]
timbuktu 407 tcp Timbuktu [Marc_Epard] [Marc_Epard]
timbuktu 407 udp Timbuktu [Marc_Epard] [Marc_Epard]
onmux 417 tcp Onmux [Stephen_Hanna] [Stephen_Hanna]
onmux 417 udp Onmux [Stephen_Hanna] [Stephen_Hanna]
svrloc 427 tcp Server Location [Veizades] [Veizades]
svrloc 427 udp Server Location [Veizades] [Veizades]
nnsp 433 tcp NNTP for transit servers (NNSP) [IESG] [IETF_Chair] 2018-07-06 [RFC3977]
nnsp 433 udp NNTP for transit servers (NNSP) [IESG] [IETF_Chair] 2018-07-06 [RFC3977]
comscm 437 tcp comscm [Jim_Teague] [Jim_Teague]
comscm 437 udp comscm [Jim_Teague] [Jim_Teague]
ddm-dfm 447 tcp DDM-Distributed File Management [Steven_Ritland] [Steven_Ritland]
ddm-dfm 447 udp DDM-Distributed File Management [Steven_Ritland] [Steven_Ritland]
scohelp 457 tcp scohelp [Faith_Zack] [Faith_Zack]
scohelp 457 udp scohelp [Faith_Zack] [Faith_Zack]
mylex-mapd 467 tcp mylex-mapd [Gary_Lewis] [Gary_Lewis]
mylex-mapd 467 udp mylex-mapd [Gary_Lewis] [Gary_Lewis]
scx-proxy 470 tcp scx-proxy [Scott_Narveson] [Scott_Narveson]
scx-proxy 470 udp scx-proxy [Scott_Narveson] [Scott_Narveson]
mondex 471 tcp Mondex [Bill_Reding] [Bill_Reding]
mondex 471 udp Mondex [Bill_Reding] [Bill_Reding]
ljk-login 472 tcp ljk-login [LJK] [LJK]
ljk-login 472 udp ljk-login [LJK] [LJK]
hybrid-pop 473 tcp hybrid-pop [Rami_Rubin] [Rami_Rubin]
hybrid-pop 473 udp hybrid-pop [Rami_Rubin] [Rami_Rubin]
tn-tl-w1 474 tcp tn-tl-w1
tn-tl-w2 474 udp tn-tl-w2 [Ed_Kress] [Ed_Kress]
tcpnethaspsrv 475 tcp tcpnethaspsrv [Michael_Zunke] [Michael_Zunke] 2010-07-23
tcpnethaspsrv 475 udp tcpnethaspsrv [Michael_Zunke] [Michael_Zunke] 2010-07-23
tn-tl-fd1 476 tcp tn-tl-fd1 [Ed_Kress] [Ed_Kress]
tn-tl-fd1 476 udp tn-tl-fd1 [Ed_Kress] [Ed_Kress]
ss7ns 477 tcp ss7ns [Jean_Michel_URSCH] [Jean_Michel_URSCH]
ss7ns 477 udp ss7ns [Jean_Michel_URSCH] [Jean_Michel_URSCH]
spsc 478 tcp spsc [Mike_Rieker] [Mike_Rieker]
spsc 478 udp spsc [Mike_Rieker] [Mike_Rieker]
iafserver 479 tcp iafserver
iafserver 479 udp iafserver
saft 487 tcp saft Simple Asynchronous File Transfer [Ulli_Horlacher] [Ulli_Horlacher]
saft 487 udp saft Simple Asynchronous File Transfer [Ulli_Horlacher] [Ulli_Horlacher]
retrospect 497 tcp Retrospect backup and restore service [Retrospect_Inc] [JG_Heithcock] 2012-02-02
retrospect 497 udp Retrospect backup and restore service [Retrospect_Inc] [JG_Heithcock] 2012-02-02
crs 507 tcp crs [Brad_Wright] [Brad_Wright]
crs 507 udp crs [Brad_Wright] [Brad_Wright]
talk 517 tcp like tenex link, but across machine - unfortunately, doesn't use link protocol (this is actually just a rendezvous port from which a tcp connection is established)
talk 517 udp like tenex link, but across machine - unfortunately, doesn't use link protocol (this is actually just a rendezvous port from which a tcp connection is established)
stx 527 tcp Stock IXChange [Ferdi_Ladeira] [Ferdi_Ladeira] 2022-01-25
stx 527 udp Stock IXChange [Ferdi_Ladeira] [Ferdi_Ladeira] 2022-01-25
nmsp 537 tcp Networked Media Streaming Protocol [Paul_Santinelli_Jr] [Paul_Santinelli_Jr]
nmsp 537 udp Networked Media Streaming Protocol [Paul_Santinelli_Jr] [Paul_Santinelli_Jr]
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 [RFC-ietf-dhc-rfc8415bis-12]
openvms-sysipc 557 tcp openvms-sysipc [Alan_Potter] [Alan_Potter]
openvms-sysipc 557 udp openvms-sysipc [Alan_Potter] [Alan_Potter]
banyan-rpc 567 tcp banyan-rpc [Tom_Lemaire] [Tom_Lemaire]
banyan-rpc 567 udp banyan-rpc [Tom_Lemaire] [Tom_Lemaire]
meter 570 tcp demon
meter 570 udp demon
meter 571 tcp udemon

Contact Information

ID Name Organization Contact URI Last Updated
[Alan_Potter] Alan Potter mailto:potter&movies.enet.dec.com
[Anastasios_Kotsikona] Anastasios Kotsikonas mailto:tasos&cs.bu.edu
[Bill_Reding] Bill Reding mailto:redingb&nwdt.natwest.co.uk
[Brad_Wright] Brad Wright mailto:bradwr&microsoft.com
[Chris_Ranch] Chris Ranch mailto:cranch&novell.com
[Dave_LeBlang] Dave LeBlang mailto:leglang&atria.com
[Ed_Kress] Ed Kress mailto:eskress&thinknet.com
[Faith_Zack] Faith Zack mailto:faithz&sco.com
[Ferdi_Ladeira] Ferdi Ladeira mailto:f.lad.mail&gmail.com 2022-01-25
[Gary_Lewis] Gary Lewis mailto:GaryL&hq.mylex.com
[Heinz_Wrobel] Heinz Wrobel mailto:hwrobel&gmx.de
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Jean_Michel_URSCH] Jean-Michel URSCH mailto:ursch&taec.enet.dec.com
[JG_Heithcock] JG Heithcock Retrospect, Inc. mailto:JG.Heithcock&retrospect.com 2012-02-02
[Jim_Teague] Jim Teague mailto:teague&zso.dec.com
[John_Kelly] John Kelly mailto:johnk&bellhow.com
[Keith_Boyce] Keith Boyce
[LJK] LJK Software, Cambridge, Massachusetts mailto:support&ljk.com
[Marc_Epard] Marc Epard mailto:marc&netopia.com
[Michael_Zunke] Michael Zunke mailto:michael.zunke&ealaddin.com 2010-07-23
[Mike_Rieker] Mike Rieker mailto:mikea&sp32.com
[Ole_Hellevik] Ole Hellevik mailto:oleh&interlinq.com
[Paul_Santinelli_Jr] Paul Santinelli Jr. mailto:psantinelli&narrative.com
[Rami_Rubin] Rami Rubin mailto:rami&hybrid.com
[Reinhard_Doelz] Reinhard Doelz mailto:doelz&comp.bioz.unibas.ch
[Retrospect_Inc] Retrospect, Inc. mailto:JG.Heithcock&retrospect.com 2012-02-02
[Robert_Watson] Robert Watson mailto:robert&cyrus.watson.org
[Scott_Narveson] Scott Narveson mailto:sjn&cray.com
[Simon_P_Jackson] Simon P Jackson mailto:jacko&kring.co.uk
[Soumitra_Sarkar] Soumitra Sarkar mailto:sarkar&vnet.ibm.com
[Stephen_Hanna] Stephen Hanna mailto:hanna&world.std.com
[Steven_Ritland] Steven Ritland mailto:srr&us.ibm.com
[Tom_Lemaire] Tom Lemaire mailto:toml&banyan.com
[Tomoo_Fujita] Tomoo Fujita mailto:tf&arc.bs1.fc.nec.co.jp
[Ulli_Horlacher] Ulli Horlacher mailto:framstag&rus.uni-stuttgart.de
[Veizades] mailto:veizades&ftp.com
[Zan_Oliphant] Zan Oliphant mailto:zan&accessone.com