Service Name and Transport Protocol Port Number Registry

Last Updated
2026-10-09
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
[RFC 6335]
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 [RFC 6335].

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
[RFC 6335]. According to Section 8.1.2 of [RFC 6335], System Ports are 
assigned by the "IETF Review" or "IESG Approval" procedures described in 
[RFC 8126]. User Ports are assigned by IANA using the "IETF Review" process, 
the "IESG Approval" process, or the "Expert Review" process, as per 
[RFC 6335]. Dynamic Ports are not assigned.

The registration procedures for service names and port numbers are
described in [RFC 6335].

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
emfis-data 140 udp EMFIS Data Service
emfis-cntl 141 tcp EMFIS Control Service [Gerd_Beling] [Gerd_Beling]
emfis-cntl 141 udp EMFIS Control Service [Gerd_Beling] [Gerd_Beling]
bl-idm 142 tcp Britton-Lee IDM [Susie_Snitzer] [Susie_Snitzer]
bl-idm 142 udp Britton-Lee IDM [Susie_Snitzer] [Susie_Snitzer]
iso-tp0 146 tcp ISO-IP0
iso-tp0 146 udp ISO-IP0
iso-ip 147 tcp ISO-IP [Marshall_Rose] [Marshall_Rose]
iso-ip 147 udp ISO-IP [Marshall_Rose] [Marshall_Rose]
aed-512 149 tcp AED 512 Emulation Service [Albert_G_Broscius] [Albert_G_Broscius]
aed-512 149 udp AED 512 Emulation Service [Albert_G_Broscius] [Albert_G_Broscius]
sql-net 150 tcp SQL-NET [Martin_Picard] [Martin_Picard]
sql-net 150 udp SQL-NET [Martin_Picard] [Martin_Picard]
netsc-prod 154 tcp NETSC
netsc-prod 154 udp NETSC
netsc-dev 155 tcp NETSC [Sergio_Heker] [Sergio_Heker]
netsc-dev 155 udp NETSC [Sergio_Heker] [Sergio_Heker]
knet-cmp 157 tcp KNET/VM Command/Message Protocol [Gary_S_Malkin] [Gary_S_Malkin]
knet-cmp 157 udp KNET/VM Command/Message Protocol [Gary_S_Malkin] [Gary_S_Malkin]
pcmail-srv 158 tcp PCMail Server [Mark_L_Lambert] [Mark_L_Lambert]
pcmail-srv 158 udp PCMail Server [Mark_L_Lambert] [Mark_L_Lambert]
nss-routing 159 tcp NSS-Routing [Yakov_Rekhter] [Yakov_Rekhter]
nss-routing 159 udp NSS-Routing [Yakov_Rekhter] [Yakov_Rekhter]
sgmp-traps 160 tcp SGMP-TRAPS [Marty_Schoffstahl] [Marty_Schoffstahl]
sgmp-traps 160 udp SGMP-TRAPS [Marty_Schoffstahl] [Marty_Schoffstahl]
cmip-man 163 tcp CMIP/TCP Manager
cmip-man 163 udp CMIP/TCP Manager
cmip-agent 164 tcp CMIP/TCP Agent [Amatzia_Ben_Artzi] [Amatzia_Ben_Artzi]
cmip-agent 164 udp CMIP/TCP Agent [Amatzia_Ben_Artzi] [Amatzia_Ben_Artzi]
xns-courier 165 tcp Xerox [Susie_Armstrong_2] [Susie_Armstrong_2]
xns-courier 165 udp Xerox [Susie_Armstrong_2] [Susie_Armstrong_2]
s-net 166 tcp Sirius Systems [Brian_Lloyd] [Brian_Lloyd]
s-net 166 udp Sirius Systems [Brian_Lloyd] [Brian_Lloyd]
print-srv 170 tcp Network PostScript [Brian_Reid] [Brian_Reid]
print-srv 170 udp Network PostScript [Brian_Reid] [Brian_Reid]
cl-1 172 tcp Network Innovations CL/1

IANA assigned this well-formed service name as a replacement for "cl/1".
[Kevin_DeVault] [Kevin_DeVault]
cl/1 172 tcp Network Innovations CL/1 [Kevin_DeVault] [Kevin_DeVault] This entry is an alias to "cl-1". This entry is now historic, not usable for use with many common service discovery mechanisms.
cl-1 172 udp Network Innovations CL/1

IANA assigned this well-formed service name as a replacement for "cl/1".
[Kevin_DeVault] [Kevin_DeVault]
cl/1 172 udp Network Innovations CL/1 [Kevin_DeVault] [Kevin_DeVault] This entry is an alias to "cl-1". This entry is now historic, not usable for use with many common service discovery mechanisms.
xyplex-mux 173 tcp Xyplex [Bob_Stewart] [Bob_Stewart]
xyplex-mux 173 udp Xyplex [Bob_Stewart] [Bob_Stewart]
genrad-mux 176 tcp GENRAD-MUX [Ron_Thornton] [Ron_Thornton]
genrad-mux 176 udp GENRAD-MUX [Ron_Thornton] [Ron_Thornton]
remote-kis 185 tcp Remote-KIS
remote-kis 185 udp Remote-KIS
osu-nms 192 tcp OSU Network Monitoring System [Doug_Karl] [Doug_Karl]
osu-nms 192 udp OSU Network Monitoring System [Doug_Karl] [Doug_Karl]
dn6-nlm-aud 195 tcp DNSIX Network Level Module Audit
dn6-nlm-aud 195 udp DNSIX Network Level Module Audit
dn6-smm-red 196 tcp DNSIX Session Mgt Module Audit Redir [Lawrence_Lebahn] [Lawrence_Lebahn]
dn6-smm-red 196 udp DNSIX Session Mgt Module Audit Redir [Lawrence_Lebahn] [Lawrence_Lebahn]
dls-mon 198 tcp Directory Location Service Monitor [Scott_Bellew] [Scott_Bellew]
dls-mon 198 udp Directory Location Service Monitor [Scott_Bellew] [Scott_Bellew]
at-rtmp 201 tcp AppleTalk Routing Maintenance
at-rtmp 201 udp AppleTalk Routing Maintenance
at-nbp 202 tcp AppleTalk Name Binding
at-nbp 202 udp AppleTalk Name Binding
at-3 203 tcp AppleTalk Unused
at-3 203 udp AppleTalk Unused
at-echo 204 tcp AppleTalk Echo
at-echo 204 udp AppleTalk Echo
at-5 205 tcp AppleTalk Unused
at-5 205 udp AppleTalk Unused
at-zis 206 tcp AppleTalk Zone Information
at-zis 206 udp AppleTalk Zone Information
at-7 207 tcp AppleTalk Unused
at-7 207 udp AppleTalk Unused
at-8 208 tcp AppleTalk Unused [Rob_Chandhok] [Rob_Chandhok]
at-8 208 udp AppleTalk Unused [Rob_Chandhok] [Rob_Chandhok]
z39-50 210 tcp ANSI Z39.50

IANA assigned this well-formed service name as a replacement for "z39.50".
[Mark_H_Needleman] [Mark_H_Needleman]
z39.50 210 tcp ANSI Z39.50 [Mark_H_Needleman] [Mark_H_Needleman] This entry is an alias to "z39-50". This entry is now historic, not usable for use with many common service discovery mechanisms.
z39-50 210 udp ANSI Z39.50

IANA assigned this well-formed service name as a replacement for "z39.50".
[Mark_H_Needleman] [Mark_H_Needleman]
z39.50 210 udp ANSI Z39.50 [Mark_H_Needleman] [Mark_H_Needleman] This entry is an alias to "z39-50". This entry is now historic, not usable for use with many common service discovery mechanisms.
914c-g 211 tcp Texas Instruments 914C/G Terminal

IANA assigned this well-formed service name as a replacement for "914c/g".
[Bill_Harrell] [Bill_Harrell]
914c/g 211 tcp Texas Instruments 914C/G Terminal [Bill_Harrell] [Bill_Harrell] This entry is an alias to "914c-g". This entry is now historic, not usable for use with many common service discovery mechanisms.
914c-g 211 udp Texas Instruments 914C/G Terminal

IANA assigned this well-formed service name as a replacement for "914c/g".
[Bill_Harrell] [Bill_Harrell]
914c/g 211 udp Texas Instruments 914C/G Terminal [Bill_Harrell] [Bill_Harrell] This entry is an alias to "914c-g". This entry is now historic, not usable for use with many common service discovery mechanisms.
fln-spx 221 tcp Berkeley rlogind with SPX auth
fln-spx 221 udp Berkeley rlogind with SPX auth
rsh-spx 222 tcp Berkeley rshd with SPX auth
rsh-spx 222 udp Berkeley rshd with SPX auth
225-241 Reserved 2024-12-20 [RFC 1060]
sur-meas 243 tcp Survey Measurement [Dave_Clark] [Dave_Clark]
sur-meas 243 udp Survey Measurement [Dave_Clark] [Dave_Clark]
subntbcst-tftp 247 tcp SUBNTBCST_TFTP

IANA assigned this well-formed service name as a replacement for "subntbcst_tftp".
[John_Fake] [John_Fake]
subntbcst_tftp 247 tcp SUBNTBCST_TFTP [John_Fake] [John_Fake] This entry is an alias to "subntbcst-tftp". This entry is now historic, not usable for use with many common service discovery mechanisms.
subntbcst-tftp 247 udp SUBNTBCST_TFTP

IANA assigned this well-formed service name as a replacement for "subntbcst_tftp".
[John_Fake] [John_Fake]
subntbcst_tftp 247 udp SUBNTBCST_TFTP [John_Fake] [John_Fake] This entry is an alias to "subntbcst-tftp". This entry is now historic, not usable for use with many common service discovery mechanisms.
249-255 Reserved 2024-12-20 [RFC 1060]
esro-gen 259 tcp Efficient Short Remote Operations [Mohsen_Banan] [Mohsen_Banan]
esro-gen 259 udp Efficient Short Remote Operations [Mohsen_Banan] [Mohsen_Banan]
x-bone-ctl 265 tcp X-Bone CTL [Joe_Touch] [Joe_Touch]
x-bone-ctl 265 udp X-Bone CTL [Joe_Touch] [Joe_Touch]
td-service 267 tcp Tobit David Service Layer
td-service 267 udp Tobit David Service Layer
td-replica 268 tcp Tobit David Replica [Franz_Josef_Leuders] [Franz_Josef_Leuders]
td-replica 268 udp Tobit David Replica [Franz_Josef_Leuders] [Franz_Josef_Leuders]
gist 270 udp Q-mode encapsulation for GIST messages [RFC 5971]
pt-tls 271 tcp IETF Network Endpoint Assessment (NEA) Posture Transport Protocol over TLS (PT-TLS) [IESG] [IETF_Chair] 2012-07-31 [RFC 6876]
272-279 Unassigned
http-mgmt 280 tcp http-mgmt [Adrian_Pell] [Adrian_Pell]

Contact Information

ID Name Organization Contact URI Last Updated
[Adrian_Pell] Adrian Pell mailto:PELL_ADRIAN/HP-UnitedKingdom_om6@hplb.hpl.hp.com
[Albert_G_Broscius] Albert G. Broscius mailto:broscius&dsl.cis.upenn.edu
[Amatzia_Ben_Artzi] Amatzia Ben-Artzi
[Bill_Harrell] Bill Harrell
[Bob_Stewart] Bob Stewart mailto:STEWART&xyplex.com
[Brian_Lloyd] Brian Lloyd mailto:brian&lloyd.com
[Brian_Reid] Brian Reid mailto:reid&decwrl.dec.com
[Dave_Clark] Dave Clark mailto:ddc&lcs.mit.edu
[Doug_Karl] Doug Karl mailto:KARL-D&osu-20.ircc.ohio-state.edu
[Franz_Josef_Leuders] Franz-Josef Leuders mailto:development&tobit.com
[Gary_S_Malkin] Gary S. Malkin mailto:GMALKIN&xylogics.com
[Gerd_Beling] Gerd Beling mailto:GBELING&isi.edu
[IESG] IESG mailto:iesg&ietf.org
[IETF_Chair] IETF Chair IETF mailto:chair&ietf.org
[Joe_Touch] Joe Touch mailto:touch&strayalpha.com 2020-02-07
[John_Fake] John Fake mailto:fake&us.ibm.com
[Kevin_DeVault] Kevin DeVault
[Lawrence_Lebahn] Lawrence Lebahn mailto:DIA3&paxrv-nes.navy.mil
[Mark_H_Needleman] Mark H. Needleman mailto:markn&sirsi.com
[Mark_L_Lambert] Mark L. Lambert mailto:markl&ptt.lcs.mit.edu
[Marshall_Rose] Marshall Rose mailto:mrose17&gmail.com 2024-07-29
[Martin_Picard] Martin Picard
[Marty_Schoffstahl] Marty Schoffstahl mailto:schoff&nisc.nyser.net
[Mohsen_Banan] Mohsen Banan mailto:mohsen&rostam.neda.com
[Rob_Chandhok] Rob Chandhok mailto:chandhok&gnome.cs.cmu.edu
[Ron_Thornton] Ron Thornton mailto:thornton&aerostation.org 2020-09-01
[Scott_Bellew] Scott Bellew mailto:smb&cs.purdue.edu
[Sergio_Heker] Sergio Heker mailto:heker&jvncc.csc.org
[Susie_Armstrong_2] Susie Armstrong mailto:Armstrong.wbst128&xerox.com
[Susie_Snitzer] Susie Snitzer
[Yakov_Rekhter] Yakov Rekhter mailto:Yakov&ibm.com