Table 11-7 Services & Port Numbers

SERVICES

PORT NUMBER

 

 

ECHO

7

 

 

FTP (File Transfer Protocol)

21

 

 

Telnet

23

 

 

SMTP (Simple Mail Transfer Protocol)

25

 

 

DNS (Domain Name System)

53

 

 

Finger

79

 

 

HTTP (Hyper Text Transfer protocol or WWW, Web)

80

 

 

POP3 (Post Office Protocol)

110

 

 

NNTP (Network News Transport Protocol)

119

 

 

SNMP (Simple Network Management Protocol)

161

 

 

SNMP trap

162

 

 

PPTP (Point-to-Point Tunneling Protocol)

1723

 

 

Configuring a Server behind NAT

Follow these steps to configure a server behind NAT:

Step 1. Enter 15 in the main menu to go to Menu 15 - NAT Setup.

Step 2. Enter 2 to go to Menu 15.2 - NAT Server Setup.

Step 3. Enter a port number in an unused Start Port No field. To forward only one port, enter it again in the End Port No field. To specify a range of ports, enter the last port to be forwarded in the End Port No field.

Step 4. Enter the inside IP address of the server in the IP Address field. In the following figure, you have a computer acting as an FTP, Telnet and SMTP server (ports 21, 23 and 25) at 192.168.1.33.

Step 5. Press [ENTER] at the “Press ENTER to confirm …” prompt to save your configuration after you define all the servers or press [ESC] at any time to cancel.

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NAT