Nat

NAT = Network Address Translation

Network address translation (NAT) is a method of remapping an IP address space into another by modifying network address information in the IP header of packets while they are in transit across a traffic routing device.

The technique was originally used to avoid the need to assign a new address to every host when a network was moved, or when the upstream Internet service provider was replaced, but could not route the networks address space.

It has become a popular and essential tool in conserving global address space in the face of IPv4 address exhaustion.

One Internet-routable IP address of a NAT gateway can be used for an entire private network.

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