Reference Manual for the Model RP614 Web Safe Router
B-8 Network and Routing Basics
Single IP Address Operation Using NAT
In the past,if multiple PCs on a LAN needed to access the Internet simultaneously,you had to
obtain a rangeof IP addressesfrom the ISP. This type of Internet account is more costly than a
single-addressaccount typically used by a single user with a modem, rather than a router.The
Model RP614 routeremploys an address-sharing method called Network Address Translation
(NAT).This method allows several networked PCs to sharean Internet account using only a single
IP address,which may be statically or dynamically assigned by your ISP.
The router accomplishesthis address sharing by translating the internal LAN IP addresses to a
singleaddress that is globally unique on the Internet. The internal LAN IP addresses can be either
privateaddresses or registered addresses. For more information about IP address translation, refer
to RFC 1631, The IPNetwork Address Translator (NAT).
The following figure illustrates a single IP address ope ration.
Figure B-3. Single IP Address Operation Using NAT
7786EA
1
92.168.0.2
1
92.168.0.3
1
92.168.0.4
1
92.168.0.5
192.168.0.1 172.21.15.105
Private IP addresses
assigned by user
Internet
IP addresses
assigned by ISP