What is port forwarding and when is it used?

• A. Blocking inbound traffic at firewall
• B. Replacing NAT with public address
• C. Direct inbound traffic from public IP/port to internal host/port; used for hosting services behind NAT
• D. Translating domain names to IP addresses

Answer: (C)

Port forwarding is the process of taking inbound traffic addressed to a specific public IP and port and delivering it to a designated device inside a private network on a chosen internal port. This lets services that live behind a NAT router become reachable from outside, by creating a map from the external port to an internal host and port. The statement that matches this exactly describes directing inbound traffic from the public IP and port to an internal host and port, and notes it’s used for hosting services behind NAT. The other ideas don’t fit: blocking inbound traffic is about security rules, not forwarding; replacing NAT with a public address removes the NAT layer rather than enabling the forward; and translating domain names to IP addresses is DNS, not port forwarding.