Prestige 310 Broadband Sharing Gateway

Many residential broadband ISP accounts do not allow you to run any server processes (such as a Web or FTP server) from your location. Your ISP may periodically check for servers and may suspend your account if it discovers any active services at your location. If you are unsure, refer to your ISP.

The most often used port numbers are shown in the following table. Please refer to RFC 1700 for further information about port numbers. Please also refer to the included disk for more examples and details on NAT.

Table 6-7 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

 

 

6.4.1 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.

Network Address Translation (NAT)

6-13