What is the primary purpose of Network Address Translation (NAT)?

The primary purpose of Network Address Translation (NAT) is to translate private IP addresses to a public address. This process allows devices on a local network that use private IP addresses (which are not routable on the internet) to communicate over the internet. When a device sends a request to the outside world, NAT modifies the private IP address in the packet to a public IP address assigned to the NAT device (such as a router). This way, the external network sees the request as coming from the public IP, while the internal devices remain hidden and can continue to communicate using their private addresses.

NAT plays a crucial role in conserving the limited supply of public IP addresses, as multiple devices on a local network can share a single public IP address when accessing external resources. This functionality makes NAT essential for home and business networks that use private addressing as per standards defined in CIDR (Classless Inter-Domain Routing).

While NAT can also contribute to network security by hiding the internal IP structure from outside networks, its main function is the translation of addresses. The other options do not directly capture this fundamental functionality of NAT.