Network Port Number Assignment

The Well-Known Ports are assigned by the IANA.

Ports are used in TCP or UDP communications to name the ends of logical connections that transfer data. For the purpose of providing services to unknown clients, ports were created. Table C.1 specifies the port used by the server process as its contact port. The contact port is sometimes called a Well-Known Port.

The assigned ports use a small portion of the possible port numbers. For many years the assigned ports were in the range 0-255. The range for assigned ports managed by the IANA has been expanded to the range 0-1023. The list in Table C.1 contains most of the port assignments that are significant to the Windows 2000 operating system.

Table C.1 Well-Known Ports

Port No.

Protocol

Service Name

Aliases

Comment

7

TCP

echo

Echo

7

UDP

echo

Echo

9

TCP

discard

sink null

Discard

9

UDP

discard

sink null

Discard

13

TCP

daytime

Daytime

13

UDP

daytime

Daytime

17

TCP

qotd

quote

Quote of the day

17

UDP

qotd

quote

Quote of the day

19

TCP

chargen

ttytst source

Character generator

19

UDP

chargen

ttytst source

Character generator

20

TCP

ftp-data

File Transfer

21

TCP

ftp

FTP Control

23

TCP

telnet

Telnet

25

TCP

smtp

mail

Simple Mail Transfer

37

TCP

time

Time

37

UDP

time

Time

39

UDP

rlp

resource

Resource Location Protocol

42

TCP

nameserver

name

Host Name Server

42

UDP

nameserver

name

Host Name Server

43

TCP

nicname

whois

Who Is

53

TCP

domain

Domain Name

53

UDP

domain

Domain Name Server

67

UDP

bootps

dhcps

Bootstrap Protocol Server

68

UDP

bootpc

dhcpc

Bootstrap Protocol Client

69

UDP

tftp

Trivial File Transfer

70

TCP

gopher

Gopher

79

TCP

finger

Finger

80

TCP

http

www, http

World Wide Web

88

TCP

kerberos

krb5

Kerberos

88

UDP

kerberos

krb5

Kerberos

101

TCP

hostname

hostnames

NIC Host Name Server

102

TCP

iso-tsap

ISO-TSAP Class 0

107

TCP

rtelnet

Remote Telnet Service

109

TCP

pop2

postoffice

Post Office Protocol - Version 2

110

TCP

pop3

postoffice

Post Office Protocol - Version 3

111

TCP

sunrpc

rpcbind portmap

SUN Remote Procedure Call

111

UDP

sunrpc

rpcbind portmap

SUN Remote Procedure Call

113

TCP

auth

ident tap

Authentication Sevice

117

TCP

uucp-path

UUCP Path Service

119

TCP

nntp

usenet

Network News Transfer Protocol

123

UDP

ntp

Network Time Protocol

135

TCP

epmap

loc-srv

DCE endpoint resolution

135

UDP

epmap

loc-srv

DCE endpoint resolution

137

TCP

netbios-ns

nbname

NETBIOS Name Service

137

UDP

netbios-ns

nbname

NETBIOS Name Service

138

UDP

netbios-dgm

nbdatagram

NETBIOS Datagram Service

139

TCP

netbios-ssn

nbsession

NETBIOS Session Service

143

TCP

imap

imap4

Internet Message Access Protocol

158

TCP

pcmail-srv

repository

PC Mail Server

161

UDP

snmp

snmp

SNMP

162

UDP

snmptrap

snmp-trap

SNMP TRAP

170

TCP

print-srv

Network PostScript

179

TCP

bgp

Border Gateway Protocol

194

TCP

irc

Internet Relay Chat Protocol

213

UDP

ipx

IPX over IP

389

TCP

ldap

Lightweight Directory Access Protocol

443

TCP

https

MCom

443

UDP

https

MCom

445

TCP

Microsoft CIFS

445

UDP

Microsoft CIFS

464

TCP

kpasswd

Kerberos (v5)

464

UDP

kpasswd

Kerberos (v5)

500

UDP

isakmp

ike

Internet Key Exchange (IPSec)

512

TCP

exec

Remote Process Execution

512

UDP

biff

comsat

Notifies users of new mail

513

TCP

login

Remote Login

513

UDP

who

whod

Database of who's logged on, average load

514

TCP

cmd

shell

Automatic Authentication

514

UDP

syslog

515

TCP

printer

spooler

Listens for incoming connections

517

UDP

talk

Establishes TCP Connection

518

UDP

ntalk

520

TCP

efs

Extended File Name Server

520

UDP

router

router routed

RIPv.1, RIPv.2

525

UDP

timed

timeserver

Timeserver

526

TCP

tempo

newdate

Newdate

530

TCP,UDP

courier

rpc

RPC

531

TCP

conference

chat

IRC Chat

532

TCP

netnews

readnews

Readnews

533

UDP

netwall

For emergency broadcasts

540

TCP

uucp

uucpd

Uucpd

543

TCP

klogin

Kerberos login

544

TCP

kshell

krcmd

Kerberos remote shell

550

UDP

new-rwho

new-who

New-who

556

TCP

remotefs

rfs rfs_server

Rfs Server

560

UDP

rmonitor

rmonitord

Rmonitor

561

UDP

monitor

636

TCP

ldaps

sldap

LDAP over TLS/SSL

749

TCP

kerberos-adm

Kerberos administration

749

UDP

kerberos-adm

Kerberos administration

Top Of Page

List of Well-Known TCP Port Numbers

Updated November 02, 2017 / Posted June 24, 2010

By - Webopedia Staff

Port numbers 0 to 1024 are reserved for privileged services and designated as well-known ports. This list of port numbers  are specified in RFC 1700.

In TCP/IP and UDP networks, a port is an endpoint to a logical connection and the way a client program specifies a specific server program on a computer in a network. The port number identifies what type of port it is. For example, port 80 is used for HTTP traffic. Some ports have numbers that are assigned to them by the IANA, and these are called the "well-known ports" which are specified in RFC 1700.

List of Well-Known Ports

Port numbers range from 0 to 65535, but only port numbers 0 to 1023 are reserved for privileged services and designated as well-known ports. The following list of well-known port numbers specifies the port used by the server process as its contact port.

  • Well-known ports range from 0 through 1023.
  • Registered ports are 1024 to 49151.
  • Dynamic ports (also called private ports) are 49152 to 65535.

For further information, see RFC 1700.







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