What is the purpose of Network Address Translation (NAT) A. To translate addresses between private and public IP address realms. B. To relieve the problem of IP address shortage. C. To connect a private network to the Internet. D. To provide communication between private networks and the Internet.

The purpose of Network Address Translation (NAT) is all of the above.

A. NAT translates addresses between private and public IP address realms. This means it converts the private (not globally unique) addresses in an internal network into legal public IP addresses before sending them to another network.

B. NAT helps to relieve the problem of IP address shortage. With NAT, thousands of private IP addresses can be represented by some hundreds of public IP addresses.

C. NAT is used to connect a private network to the Internet. It allows a single device, such as a router, to act as an agent between the Internet and a local network, which means that only a single unique IP address is required to represent an entire group of computers to anything outside their network.

D. NAT provides communication between private networks and the Internet. It allows the private IP space to be reused, enabling communication with the outside world through the use of a single public IP address.