Which NAT configuration is most appropriate for servers that must remain reachable from the public internet?

Which NAT configuration is most appropriate for servers that must remain reachable from the public internet?

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

Answer: (B)

The central idea is that a server that must stay reachable from the public internet needs a fixed public address that external users can consistently connect to. Static NAT provides exactly that: a permanent one-to-one mapping between the server’s private IP and a designated public IP. Because this mapping never changes, external clients always reach the same public IP, which the router translates to the server’s private IP, ensuring reliable inbound access. This stability also makes firewall rules and other access controls straightforward to configure, since the destination address remains constant. If you used dynamic NAT, the public IP assigned to the server can change as addresses are drawn from a pool, which can break reachability unless you constantly update DNS or reconfigure clients—clearly not ideal for servers that must remain reachable. Port Address Translation (PAT) uses a single public IP for many internal hosts and relies on port numbers to distinguish connections; while it’s convenient for outbound connections, inbound access to a specific server becomes more complex and generally requires explicit port forwarding, which isn’t as scalable or reliable for servers that must be continuously reachable. The option described as NAT Network Address Translation isn’t a standard approach for ensuring a fixed inbound mapping to a server.

The central idea is that a server that must stay reachable from the public internet needs a fixed public address that external users can consistently connect to. Static NAT provides exactly that: a permanent one-to-one mapping between the server’s private IP and a designated public IP. Because this mapping never changes, external clients always reach the same public IP, which the router translates to the server’s private IP, ensuring reliable inbound access. This stability also makes firewall rules and other access controls straightforward to configure, since the destination address remains constant.

If you used dynamic NAT, the public IP assigned to the server can change as addresses are drawn from a pool, which can break reachability unless you constantly update DNS or reconfigure clients—clearly not ideal for servers that must remain reachable. Port Address Translation (PAT) uses a single public IP for many internal hosts and relies on port numbers to distinguish connections; while it’s convenient for outbound connections, inbound access to a specific server becomes more complex and generally requires explicit port forwarding, which isn’t as scalable or reliable for servers that must be continuously reachable. The option described as NAT Network Address Translation isn’t a standard approach for ensuring a fixed inbound mapping to a server.