Common Port Assignments

Table D-1 lists currently assigned Transmission Control Protocol (TCP) port numbers. To the extent possible, the User Datagram Protocol (UDP) uses the same numbers.

 

Table D-1 Currently Assigned TCP and UDP Port Numbers

Port
Keyword
Description

0

—

Reserved

1–4

—

Unassigned

5

RJE

Remote job entry

7

ECHO

Echo

9

DISCARD

Discard

11

USERS

Active users

13

DAYTIME

Daytime

15

NETSTAT

Who is up or NETSTAT

17

QUOTE

Quote of the day

19

CHARGEN

Character generator

20

FTP-DATA

File Transfer Protocol (data)

21

FTP

File Transfer Protocol

23

TELNET

Terminal connection

25

SMTP

Simple Mail Transport Protocol

37

TIME

Time

39

RLP

Resource Location Protocol

42

NAMESERVER

Hostname server

43

NICNAME

Who is

49

LOGIN

Login Host Protocol

53

DOMAIN

Domain name server

67

BOOTPS

Bootstrap Protocol Server

68

BOOTPC

Bootstrap Protocol Client

69

TFTP

Trivial File Transfer Protocol

75

—

Any private dial-out service

77

—

Any private RJE service

79

FINGER

Finger

95

SUPDUP

SUPDUP Protocol

101

HOST NAME

Network interface card (NIC) hostname server

102

ISO-TSAP

ISO-Transport Service Access Point (TSAP)

103

X400

X400

104

X400-SND

X400-SND

111

SUNRPC

Sun Microsystems Remote Procedure Call

113

AUTH

Authentication service

117

UUCP-PATH

UNIX-to-UNIX Copy Protocol (UUCP) Path Service

119

NNTP

Usenet Network News Transfer Protocol

123

NTP

Network Time Protocol

126

SNMP

Simple Network Management Protocol

137

NETBIOS-NS

NetBIOS name service

138

NETBIOS-DGM

NetBIOS datagram service

139

NETBIOS-SSN

NetBIOS session service

161

SNMP

Simple Network Management Protocol

162

SNMP-TRAP

Simple Network Management Protocol traps

512

rexec

UNIX remote execution (control)

513

TCP—rlogin
UDP—rwho

TCP—UNIX remote login

UDP—UNIX broadcast name service

514

TCP—rsh
UDP—syslog

TCP—UNIX remote shell

UDP—system log

515

Printer

UNIX line printer remote spooling

520

RIP

Routing Information Protocol

525

Timed

Time server