Watchguard Network Security Practice Test

Which form of NAT is most suitable if you require one-to-one mapping of an internal and external IP?

1. Static NAT

2. Dynamic NAT

3. NAT Loopback

4. Source NAT

The correct answer is: Static NAT

Choosing static NAT is appropriate when you need a one-to-one mapping of an internal IP address to an external IP address. This form of NAT establishes a permanent link between a specific internal IP address and a specific external IP address, ensuring that incoming traffic directed to the external address is consistently forwarded to the designated internal device. Static NAT is particularly useful for hosting servers or services that need to be accessible from the outside internet, such as web servers, mail servers, or any devices that require a reliable and predictable external address. With static NAT, the configuration does not change unless a network administrator intentionally alters it, making it a stable solution for applications that require consistent access. In contrast, other forms of NAT, such as dynamic NAT, do not offer a permanent mapping. Dynamic NAT assigns IP addresses from a pool based on availability, which can lead to changes in the external IP address assigned to an internal device. NAT Loopback is primarily used for accessing internal resources through their external IP from within the same network and doesn’t create one-to-one mappings for external access. Source NAT modifies the source address of outbound packets, but it doesn’t facilitate the same one-to-one correspondence between internal and external addresses as static NAT does.