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Port Assignments for Well-Known Ports

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

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