Netgear FM114P FR114W Reference Manual - Page 134

Single IP Address Operation Using NAT

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Reference Manual for the Model FR114P, FR114W and FM114P Cable/DSL ProSafe Firewall Family 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 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 FR114P Firewall 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. Private IP addresses assigned by user 192.168.0.2 IP addresses assigned by ISP 192.168.0.3 192.168.0.4 192.168.0.1 172.21.15.105 Internet 192.168.0.5 Figure B-3. Single IP Address Operation Using NAT 7786EA B-8 Networks, Routing, and Firewall Basics

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Reference Manual for the Model FR114P, FR114W and FM114P Cable/DSL ProSafe Firewall Family
B-8
Networks, Routing, and Firewall 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 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
FR114P Firewall 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.
Figure B-3.
Single IP Address Operation Using NAT
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