Figure 1-3. Single Ip Address Operation Using Nat - NETGEAR RT338 Reference Manual

The router accomplishes address sharing by translating the internal LAN IP addresses to a single
address that is globally unique on the Internet. The internal LAN IP addresses can be either private
addresses or registered addresses. For more information about IP address translation, refer to RFC
1631, The IP Network Address Translator (NAT).
Figure 1-3 illustrates a single IP address operation.
192.168.0.2
192.168.0.3
192.168.0.4
192.168.0.5
Figure 1-3. Single IP Address Operation Using NAT
This scheme offers the additional benefit of protection similar to that of a firewall. Internal LAN
addresses are not available to the Internet through the translated connection. All incoming
inquiries are filtered out by the router. Filtering can prevent intruders from probing your system.
You can use the port forwarding feature to allow specific services (for example, a Web server) on
your local network to be accessible to outside users.
Introduction
Private IP addresses
assigned by user
192.168.0.1 172.21.15.105
Reference Guide for the Model RT338 ISDN Router
IP addresses
assigned by ISP
Internet
7786EA
1-13