well-known port numbers

Definition of well-known port numbers in The Network Encyclopedia.

What is Well-known port numbers?

Well-known port numbers are port numbers for Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) that have been assigned to specific TCP/IP applications or services by the Internet Assigned Numbers Authority (IANA). Well-known port numbers are assigned within the range 0 through 1023 and are specified in Request for Comments (RFC) 1060. (The total range of possible port numbers is 0 through 65535.) The following table describes some of the well-known port numbers.

NOTE

“Registered ports” are port numbers that are not controlled by IANA but that IANA registers to indicate to the Internet community which vendor applications use them. Registered ports range from 1024 through 65535 and can be used by any process or program requesting it if the operating system has not already allocated it for a specific use. Programs and processes that communicate using remote procedure calls (RPCs) often randomly select a registered port for each RPC communication session.

Port Number List

Well-Known Port Numbers

Port Number Keyword Description
0/tcp, udp
 
Reserved
1/tcp, udp
tcpmux
TCP Port Service Multiplexer
2/tcp, udp
compressnet
Management Utility
3/tcp, udp
compressnet
Compression Process
4/tcp, udp
 
Unassigned
5/tcp, udp
rje
Remote Job Entry
6/tcp, udp
 
Unassigned
7/tcp, udp
echo
Echo
8/tcp, udp
 
Unassigned
9/tcp, udp
discard
Discard; alias = sink null
10/tcp, udp
 
Unassigned
11/tcp, udp
systat
Active Users; alias = users
12/tcp, udp
 
Unassigned
13/tcp, udp
daytime
Daytime
14/tcp, udp
 
Unassigned
15/tcp, udp
 
Unassigned (was netstat)
16/tcp, udp
 
Unassigned
17/tcp, udp
qotd
Quote of the Day; alias = quote
18/tcp, udp
msp
Message Send Protocol
19/tcp, udp
chargen
Character Generator; alias = ttytst source
20/tcp, udp
ftp-data
File Transfer (default data)
21/tcp, udp
ftp
File Transfer (control), connection dialog
22/tcp, udp
 
Unassigned
23/tcp, udp
telnet
Telnet
24/tcp, udp
 
Any private mail system
25/tcp, udp
smtp
Simple Mail Transfer; alias = mail
26/tcp, udp
 
Unassigned
27/tcp, udp
nsw-fe
NSW User System FE
28/tcp, udp
 
Unassigned
29/tcp, udp
msg-icp
MSG ICP
30/tcp, udp
 
Unassigned
31/tcp, udp
msg-auth
MSG Authentication
32/tcp, udp
 
Unassigned
33/tcp, udp
dsp
Display Support Protocol
34/tcp, udp
 
Unassigned
35/tcp, udp
 
Any private printer server
36/tcp, udp
 
Unassigned
37/tcp, udp
time
Time; alias = timeserver
38/tcp, udp
 
Unassigned
39/tcp, udp
rlp
Resource Location Protocol; alias = resource
40/tcp, udp
 
Unassigned
41/tcp, udp
graphics
Graphics
42/tcp, udp
nameserver
Host Name Server; alias = nameserver
43/tcp, udp
nicname
Who Is; alias = nicname
44/tcp, udp
mpm-flags
MPM FLAGS Protocol
45/tcp, udp
mpm
Message Processing Module
46/tcp, udp
mpm-snd
MPM (default send)
47/tcp, udp
ni-ftp
NI FTP
48/tcp, udp
 
Unassigned
49/tcp, udp
login
Login Host Protocol
50/tcp, udp
re-mail-ck
Remote Mail Checking Protocol
51/tcp, udp
la-maint
IMP Logical Address Maintenance
52/tcp, udp
xns-time
XNS Time Protocol
53/tcp, udp
domain
Domain Name Server
54/tcp, udp
xns-ch
XNS Clearinghouse
55/tcp, udp
isi-gl
ISI Graphics Language
56/tcp, udp
xns-auth
XNS Authentication
57/tcp, udp
 
Any private terminal access
58/tcp, udp
xns-mail
XNS Mail
59/tcp, udp
 
Any private file service
60/tcp, udp
 
Unassigned
61/tcp, udp
ni-mail
NI MAIL
62/tcp, udp
acas
ACA Services
63/tcp, udp
via-ftp
VIA Systems – FTP
64/tcp, udp
covia
Communications Integrator (CI)
65/tcp, udp
tacacs-ds
TACACS-Database Service
66/tcp, udp
sql*net
Oracle SQL*NET
67/tcp, udp
bootpc
DHCP/BOOTP Protocol Server
68/tcp, udp
bootpc
DHCP/BOOTP Protocol Server
69/tcp, udp
tftp
Trivial File Transfer
70/tcp, udp
gopher
Gopher
71/tcp, udp
netrjs-1
Remote Job Service
72/tcp, udp
netrjs-2
Remote Job Service
73/tcp, udp
netrjs-3
Remote Job Service
74/tcp, udp
netrjs-4
Remote Job Service
75/udp
 
Any private dial-out service
76/tcp, udp
 
Unassigned
77/tcp, udp
 
Any private RJE service
78/tcp, udp
vettcp
Vettcp
79/tcp, udp
finger
Finger
80/tcp, udp
www
World Wide Web HTTP
81/tcp, udp
hosts2-ns
HOSTS2 Name Server
82/tcp, udp
xfer
XFER Utility
83/tcp, udp
mit-ml-dev
MIT ML Device
84/tcp, udp
ctf
Common Trace Facility
85/tcp, udp
mit-ml-dev
MIT ML Device
86/tcp, udp
mfcobol
Micro Focus Cobol
87/tcp, udp
 
Any private terminal link; alias = ttylink
88/tcp, udp
kerberos
Kerberos
89/tcp, udp
su-mit-tg
SU/MIT Telnet Gateway
     
90/tcp, udp
 
DNSIX Security Attribute Token Map
91/tcp, udp
mit-dov
MIT Dover Spooler
92/tcp, udp
npp
Network Printing Protocol
93/tcp, udp
dcp
Device Control Protocol
94/tcp, udp
objcall
Tivoli Object Dispatcher
95/tcp, udp
supdup
SUPDUP
96/tcp, udp
dixie
DIXIE Protocol Specification
97/tcp, udp
swift-rvf
Swift Remote Virtual File Protocol
98/tcp, udp
tacnews
TAC News
99/tcp, udp
metagram
Metagram Relay
100/tcp
newacct
(unauthorized use)
101/tcp, udp
hostname
NIC Host Name Server; alias = hostname
102/tcp, udp
iso-tsap
ISO-TSAP
103/tcp, udp
gppitnp
Genesis Point-to-Point Trans Net; alias = webster
104/tcp, udp
acr-nema
ACR-NEMA Digital Imag. & Comm. 300
105/tcp, udp
csnet-ns
Mailbox Name Nameserver
106/tcp, udp
3com-tsmux
3COM-TSMUX
107/tcp, udp
rtelnet
Remote Telnet Service
108/tcp, udp
snagas
SNA Gateway Access Server
109/tcp, udp
pop2
Post Office Protocol version 2 (POP2); alias = postoffice
110/tcp, udp
pop3
Post Office Protocol version 3 (POP3); alias = postoffice
111/tcp, udp
sunrpc
SUN Remote Procedure Call
112/tcp, udp
mcidas
McIDAS Data Transmission Protocol
113/tcp, udp
auth
Authentication Service; alias = authentication
114/tcp, udp
audionews
Audio News Multicast
115/tcp, udp
sftp
Simple File Transfer Protocol
116/tcp, udp
ansanotify
ANSA REX Notify
117/tcp, udp
uucp-path
UUCP Path Service
118/tcp, udp
sqlserv
SQL Services
119/tcp, udp
nntp
Network News Transfer Protocol (NNTP); alias = usenet
120/tcp, udp
cfdptkt
CFDPTKT
121/tcp, udp
erpc
Encore Expedited Remote Pro. Call
122/tcp, udp
smakynet
SMAKYNET
123/tcp, udp
ntp
Network Time Protocol; alias = ntpd ntp
124/tcp, udp
ansatrader
ANSA REX Trader
125/tcp, udp
locus-map
Locus PC-Interface Net Map Server
126/tcp, udp
unitary
Unisys Unitary Login
127/tcp, udp
locus-con
Locus PC-Interface Conn Server
128/tcp, udp
gss-xlicen
GSS X License Verification
129/tcp, udp
pwdgen
Password Generator Protocol
130/tcp, udp
cisco-fna
Cisco FNATIVE
131/tcp, udp
cisco-tna
Cisco TNATIVE
132/tcp, udp
cisco-sys
Cisco SYSMAINT
133/tcp, udp
statsrv
Statistics Service
134/tcp, udp
ingres-net
INGRES-NET Service
135/tcp, udp
loc-srv
Location Service
136/tcp, udp
profile
PROFILE Naming System
137/tcp, udp
netbios-ns
NetBIOS Name Service
138/tcp, udp
netbios-dgm
NetBIOS Datagram Service
139/tcp, udp
netbios-ssn
NetBIOS Session Service
140/tcp, udp
emfis-data
EMFIS Data Service
141/tcp, udp
emfis-cntl
EMFIS Control Service
142/tcp, udp
bl-idm
Britton-Lee IDM
143/tcp, udp
imap2
Interim Mail Access Protocol v2
144/tcp, udp
news
NewS; alias = news
145/tcp, udp
uaac
UAAC Protocol
146/tcp, udp
iso-ip0
ISO-IP0
147/tcp, udp
iso-ip
ISO-IP
148/tcp, udp
cronus
CRONUS-SUPPORT
149/tcp, udp
aed-512
AED 512 Emulation Service
150/tcp, udp
sql-net
SQL-NET
151/tcp, udp
hems
HEMS
152/tcp, udp
bftp
Background File Transfer Program
153/tcp, udp
sgmp
SGMP; alias = sgmp
154/tcp, udp
netsc-prod
Netscape
155/tcp, udp
netsc-dev
Netscape
156/tcp, udp
sqlsrv
SQL Service
157/tcp, udp
knet-cmp
KNET/VM Command/Message Protocol
158/tcp, udp
pcmail-srv
PCMail Server; alias = repository
159/tcp, udp
nss-routing
NSS-Routing
160/tcp, udp
sgmp-traps
SGMP-TRAPS
161/tcp, udp
snmp
SNMP; alias = snmp
162/tcp, udp
snmptrap
SNMPTRAP
163/tcp, udp
cmip-man
CMIP/TCP Manager
164/tcp, udp
cmip-agent
CMIP/TCP Agent
165/tcp, udp
xns-courier
Xerox
166/tcp, udp
s-net
Sirius Systems
167/tcp, udp
namp
NAMP
168/tcp, udp
rsvd
RSVD
169/tcp, udp
send
SEND
170/tcp, udp
print-srv
Network PostScript
171/tcp, udp
multiplex
Network Innovations Multiplex
172/tcp, udp
cl/1
Network Innovations CL/1
173/tcp, udp
xyplex-mux
Xyplex
174/tcp, udp
mailq
MAILQ
175/tcp, udp
vmnet
VMNET
176/tcp, udp
genrad-mux
GENRAD-MUX
177/tcp, udp
xdmcp
X Display Manager Control Protocol
178/tcp, udp
nextstep
NextStep Window Server
179/tcp, udp
bgp
Border Gateway Protocol (BGP)
180/tcp, udp
ris
Intergraph
181/tcp, udp
unify
Unify
182/tcp, udp
audit
Unisys Audit SITP
183/tcp, udp
ocbinder
OCBinder
184/tcp, udp
ocserver
OCServer
185/tcp, udp
remote-kis
Remote-KIS
186/tcp, udp
kis
KIS Protocol
187/tcp, udp
aci
Application Communication Interface
188/tcp, udp
mumps
Plus Five’s MUMPS
189/tcp, udp
qft
Queued File Transport
190/tcp, udp
gacp
Gateway Access Control Protocol
191/tcp, udp
prospero
Prospero
192/tcp, udp
osu-nms
OSU Network Monitoring System
193/tcp, udp
srmp
Spider Remote Monitoring Protocol
194/tcp, udp
irc
Internet Relay Chat (IRC) Protocol
195/tcp, udp
dn6-nlm-aud
DNSIX Network Level Module Audit
196/tcp, udp
dn6-smm-red
DNSIX Session Mgt Module Audit Redir
197/tcp, udp
dls
Directory Location Service
198/tcp, udp
dls-mon
Directory Location Service Monitor
199/tcp, udp
smux
SMUX
200/tcp, udp
src
IBM System Resource Controller
201/tcp, udp
at-rtmp
AppleTalk Routing Maintenance
202/tcp, udp
at-nbp
AppleTalk Name Binding
203/tcp, udp
at-3
AppleTalk Unused
204/tcp, udp
at-echo
AppleTalk Echo
205/tcp, udp
at-5
AppleTalk Unused
206/tcp, udp
at-zis
AppleTalk Zone Information
207/tcp, udp
at-7
AppleTalk Unused
208/tcp, udp
at-8
AppleTalk Unused
209/tcp, udp
tam
Trivial Authenticated Mail Protocol
210/tcp, udp
z39.50
ANSI Z39.50
211/tcp, udp
914c/g
Texas Instruments 914C/G Terminal
212/tcp, udp
anet
ATEXSSTR
213/tcp, udp
ipx
Internetwork Packet Exchange (IPX)
214/tcp, udp
vmpwscs
VM PWSCS
215/tcp, udp
softpc
Insignia Solutions
216/tcp, udp
atls
Access Technology License Server
217/tcp, udp
dbase
dBASE UNIX
218/tcp, udp
mpp
Netix Message Posting Protocol
219/tcp, udp
uarps
Unisys ARPs
220/tcp, udp
imap3
Interactive Mail Access Protocol v3
221/tcp, udp
fln-spx
Berkeley rlogind with SPX auth
222/tcp, udp
fsh-spx
Berkeley rshd with SPX auth
223/tcp, udp
cdc
Certificate Distribution Center
224–241
 
Reserved
243/tcp, udp
sur-meas
Survey Measurement
245/tcp, udp
link
LINK
246/tcp, udp
dsp3270
Display Systems Protocol
247–255
 
Reserved
345/tcp, udp
pawserv
Perf Analysis Workbench
346/tcp, udp
zserv
Zebra server
347/tcp, udp
fatserv
Fatmen Server
371/tcp, udp
clearcase
Clearcase
372/tcp, udp
ulistserv
UNIX Listserv
373/tcp, udp
legent-1
Legent Corporation
374/tcp, udp
legent-2
Legent Corporation
512/tcp
print
Microsoft Windows NT Server and Windows NT Workstation 4 can send LPD client print jobs from any available reserved port between 512 and 1023; see also the description for ports 721 to 731
512/udp
biff
Used by the mail system to notify users of new mail received; currently receives messages only from processes on the same computer; alias = comsat
513/tcp
login
Remote logon such as Telnet; automatic authentication performed based on privileged port numbers and distributed databases that identify “authentication domains”
513/udp
who
Maintains databases showing who’s logged on to the computers on a local net and the load average of the computer; alias = whod
514/tcp
cmd
Like exec, but automatic authentication is performed as for logon server
514/udp
syslog
 
515/tcp, udp
printer
Spooler; the print server LPD service listens on tcp port 515 for incoming connections; alias = spooler
517/tcp, udp
talk
Like tenex link, but across computers; unfortunately, doesn’t use link protocol (actually just a rendezvous port from which a TCP connection is established)
518/tcp, udp
ntalk
 
519/tcp, udp
utime
Unixtime
520/tcp
efs
Extended filename server
520/udp
router
Local routing process (on site); uses variant of Xerox NS routing information protocol; alias = router routed
525/tcp, udp
timed
Timeserver
526/tcp, udp
tempo
Newdate
530/tcp, udp
courier
RPC
531/tcp
conference
Chat
531/udp
rvd-control
MIT disk
532/tcp, udp
netnews
Readnews
533/tcp, udp
netwall
For emergency broadcasts
540/tcp, udp
uucp
Uucpd
543/tcp, udp
klogin
 
544/tcp, udp
kshell
Krcmd; alias = cmd
550/tcp, udp
new-rwho
New-who
555/tcp, udp
dsf
 
556/tcp, udp
remotefs
Rfs server; alias = rfs_server rfs
560/tcp, udp
rmonitor
Rmonitord
561/tcp, udp
monitor
 
562/tcp, udp
chshell
Chcmd
564/tcp, udp
9pfs
Plan 9 file service
565/tcp, udp
whoami
Whoami
570/tcp, udp
meter
Demon
571/tcp, udp
meter
Udemon
600/tcp, udp
ipcserver
Sun IPC server
607/tcp, udp
nqs
Nqs
666/tcp, udp
doom
Reserved for Id software
704/tcp, udp
elcsd
Errlog copy/server daemon
721–731/tcp
printer
In Windows NT 3.5, all TCP/IP print jobs sent from a computer running Windows NT were sourced from TCP ports 721 through 731; Windows NT 4 and Windows 2000 source LPD client print jobs from any available reserved port between 512 and 1023
740/tcp, udp
netcp
NETscout Control Protocol
741/tcp, udp
netgw
NetGW
742/tcp, udp
netrcs
Network-based Rev. Cont. Sys.
744/tcp, udp
flexlm
Flexible License Manager
747/tcp, udp
fujitsu-dev
Fujitsu Device Control
748/tcp, udp
ris-cm
Russell Info Sci Calendar Manager
749/tcp, udp
kerberos-adm
Kerberos administration
750/tcp
rfile
Kerberos authentication; alias = kdc
750/udp
loadav
 
751/tcp, udp
pump
Kerberos authentication
752/tcp, udp
qrh
Kerberos password server
753/tcp, udp
rrh
Kerberos userreg server
754/tcp, udp
tell
Send; Kerberos slave propagation
758/tcp, udp
nlogin
 
759/tcp, udp
con
 
760/tcp, udp
ns
 
761/tcp, udp
rxe
 
762/tcp, udp
quotad
 
763/tcp, udp
cycleserv
 
764/tcp, udp
omserv
 
765/tcp, udp
webster
 
767/tcp, udp
phonebook
Phone
769/tcp, udp
vid
 
770/tcp, udp
cadlock
 
771/tcp, udp
rtip
 
772/tcp, udp
cycleserv2
 
773/tcp
submit
 
773/udp
notify
 
774/tcp
rpasswd
 
774/udp
acmaint_dbd
 
775/tcp
entomb
 
775/udp
acmaint_transd
 
776/tcp, udp
wpages
 
780/tcp, udp
wpgs
 
781/tcp, udp
hp-collector
HP performance data collector
782/tcp, udp
hp-managed-node
HP performance data managed node
783/tcp, udp
hp-alarm-mgr
HP performance data alarm manager
800/tcp, udp
mdbs_daemon
 
801/tcp, udp
device
 
888/tcp
erlogin
Logon and environment passing
996/tcp, udp
xtreelic
XTREE License Server
997/tcp, udp
maitrd
 
998/tcp
busboy
 
998/udp
puparp
 
999/tcp
garcon
 
999/udp
applix
Applix ac
999/tcp, udp
puprouter
 
1000/tcp
cadlock
 
1000/udp
ock