Netgear RT314 Manual Do Utilizador

Reference Guide for the Model FR314 Cable/DSL Firewall Router

B-8

Network and Routing Basics

In the past, if multiple PCs on a LAN needed to access the Internet simultaneously, you had to 
obtain a range of IP addresses from the ISP. This type of Internet account is more costly than a 
single-address account typically used by a single user with a modem, rather than a router. The 
FR314 firewall router employs an address-sharing method called Network Address Translation 
(NAT). This method allows several networked PCs to share an Internet account using only a single 
IP address, which may be statically or dynamically assigned by your ISP.

The router accomplishes this 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).

The following figure illustrates a single IP address operation.

 

7786EA

192.168.0.2

192.168.0.3

192.168.0.4

192.168.0.5

192.168.0.1

172.21.15.105

Private IP addresses
assigned by user

Internet

IP addresses
assigned by ISP