Private IP addresses have been reserved for internal LAN address use, as outlined in RFC 1918. These addresses can be used within the boundaries of a company, but they cannot be used on the Internet because they will not be properly routed. NAT enables a company to use these private addresses and still be able to communicate transparently with computers on the Internet.

The following lists current private IP address ranges:

10.0.0.0–10.255.255.255 Class A network

172.16.0.0–172.31.255.255 16 contiguous Class B networks

192.168.0.0–192.168.255.255 256 contiguous Class C networks

NAT is a gateway that lies between a network and the Internet (or another network) that performs transparent routing and address translation. Because IP addresses ...

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