What NAT type provides a one-to-one mapping between a private IP address and a public IP address, suitable for servers that must be reachable?

What NAT type provides a one-to-one mapping between a private IP address and a public IP address, suitable for servers that must be reachable?

• A. Dynamic NAT
• B. NAT Network Address Translation
• C. Static NAT
• D. PAT Port Address Translation

Answer: (C)

Static NAT provides a fixed one-to-one mapping between a private IP and a public IP, which is essential for servers that must be reachable from outside the network. With this setup, a specific internal host always appears on the same public address, so external clients can reliably reach the service (no port translation involved). This makes it the best choice when consistent inbound reachability is required. Dynamic NAT, by contrast, maps internal addresses to a public IP from a pool and can change over time, so reachability isn’t guaranteed. PAT (Port Address Translation) lets many private hosts share a single public IP by using different ports, which complicates direct access to a particular internal server unless you implement additional port-forwarding rules. The generic term NAT doesn’t specify a fixed one-to-one mapping, so it doesn’t guarantee the same behavior as static NAT.

Static NAT provides a fixed one-to-one mapping between a private IP and a public IP, which is essential for servers that must be reachable from outside the network. With this setup, a specific internal host always appears on the same public address, so external clients can reliably reach the service (no port translation involved). This makes it the best choice when consistent inbound reachability is required. Dynamic NAT, by contrast, maps internal addresses to a public IP from a pool and can change over time, so reachability isn’t guaranteed. PAT (Port Address Translation) lets many private hosts share a single public IP by using different ports, which complicates direct access to a particular internal server unless you implement additional port-forwarding rules. The generic term NAT doesn’t specify a fixed one-to-one mapping, so it doesn’t guarantee the same behavior as static NAT.