What is NAT used for in network design?

• A. To provide access to a network from another network
• B. To encrypt all traffic end-to-end
• C. To map IP addresses to DNS names
• D. To block all inbound connections

Answer: (A)

NAT is used to allow devices on a private network to reach external networks by translating private IP addresses to a public IP address (often with a port mapping). This lets many hosts share a single public IP when accessing the Internet, which is crucial because public IPv4 addresses are limited. NAT also hides internal addresses from the outside world, providing a basic layer of confidentiality for internal hosts. It does not encrypt traffic end-to-end, which is handled by encryption protocols like TLS. It doesn’t map IPs to DNS names (that’s DNS), and by itself it doesn’t block all inbound connections—unsolicited inbound traffic is usually blocked unless you configure exceptions such as port forwarding. In practical terms, a home router uses NAT to let multiple devices access the Internet through one public IP.