Netopia R2121, User Reference Manual

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10-2 User’s Reference Guide
Network Address Translation works by remapping the source IP address of traffic from the LAN to a single static
or dynamically assigned IP address shown to the remote side of the router.
The feature can be implemented on a per Connection Profile basis. The network router can use two or more
Connection Profiles simultaneously to connect to two or more networks. Each profile may have Network Address
Translation enabled.
When Network Address Translation is enabled, the Netopia R2121 can either use a statically assigned IP
address, or one dynamically assigned each time the router connects to the ISP. While a dynamically assigned IP
address offers the ISP more flexibility, it does have an impor tant limitation. The router will require a static IP
address to suppor t Web, FTP, or other ser vices available to the WAN. To suppor t these ser vices with Network
Address Translation enabled, a ser vice can only be associated with one machine on the LAN.
When connected to the Internet or some other large network using Network Address Translation, the individual
machines on your LAN are not directly accessible from the WAN. Network Address Translation provides an
inherently secure method of connection to the outside world.
163.167.132.1
192.168.1.100
192.168.1.102
192.168.1.103
192.168.1.104
192.168.1.105
192.168.1.106
163.167.132.1
163.167.132.1
163.167.132.2
163.167.132.2
163.167.132.3
163.167.132.3
163.167.132.4
163.167.132.4
163.167.132.5
163.167.132.5
163.167.132.6
163.167.132.6
Without NAT
With NAT
HOW NAT WORKS
ISP*
*or corporate intranet router