Wuxi MitraStar Technology Co. Ltd DSL100HNUT1V3 User Manual

Chapter 10    Network Address Translation (NAT)

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You may enter a single port number or a range of port numbers to be forwarded, and the local IP 

address of the desired server. The port number identifies a service; for example, web service is on 

port 80 and FTP on port 21. In some cases, such as for unknown services or where one server can 

support more than one service (for example both FTP and web service), it might be better to specify 

a range of port numbers. You can allocate a server IP address that corresponds to a port or a range 

of ports. Please refer to RFC 1700 for further information about port numbers. 



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.

Let's say you want to assign ports 21-25 to one FTP, Telnet and SMTP server (A in the example), port 

80 to another (B in the example) and assign a default server IP address of 10.0.0.35 to a third (C in 

the example). You assign the LAN IP addresses and the ISP assigns the WAN IP address. The NAT 

network appears as a single host on the Internet.

Figure 83 Multiple Servers Behind NAT Example

A=10.0.0.33

D=10.0.0.36

C=10.0.0.35

B=10.0.0.34

Click Network Setting > NAT to open the Port Forwarding screen.

Figure 84 Network Setting > NAT > Port Forwarding