Which statement best defines the function of NAT in routing?

NAT, or Network Address Translation, primarily functions to enable private networks to communicate over the public internet. This is achieved by translating private IP addresses used within a local network to a public IP address that is routable on the internet. In many networking scenarios, private networks employ non-routable IP addresses, which cannot be directly accessed from outside their local environment. NAT ensures that when devices within a private network make requests to the internet, those requests translate to a public IP address, allowing for seamless communication while preserving the privacy of internal network IP addresses.

This mechanism not only facilitates outbound requests but also enables the ability to manage incoming responses to those requests accurately, ensuring that they reach the correct internal device. Thus, it effectively allows multiple devices on a local network to share a single public IP address, promoting efficient use of the limited IPv4 address space. While NAT does enhance security by keeping internal IP addresses concealed, its primary purpose is enabling the communication of private networks over the public internet.