Network Address Translation (NAT)
Network Address Translation (NAT) is an Internet Protocol (IP) conservation technique that allows network users to have many IP addresses locally and one or few global addresses (Forouzan & Fegan, 2007). Network traffic within the local network setting uses the locally allocated IP addresses while all traffic going outside or entering the network uses the global address. NAT is often implemented as a bridge between the local network and global network so as to replace all local IP addresses with global IP addresses on outgoing network packets.
Example of NAT
As an example, after a user subscribes to home internet broadband, the service provider connects a network cable to a router in the home. The router assigns local addresses to all the devices connected to it, however, all network packets from the home to the internet have the same global IP address assigned by the router irrespective of which device within the network sent the traffic. The router, which acts as a NAT server to the home, connects to the service provider’s web server which is also a NAT server assigning IP addresses to subscribers and connecting them to other external servers and networks. Below is a network diagram that illustrates how NAT is implemented in a home or small organization’s network.
Forouzan, B. A., & Fegan, S. C. (2007). Data communications and networking. 4th ed. New York: McGraw-Hill Higher Education, pp.563-564.