Palo Alto Networks (PANW) Certified Network Security Administrator (PCNSA) Practice Exam

Which NAT rule configuration will allow users on the Inside zone to access a web application using its public IP address?

1. Source NAT

2. Destination NAT

3. Three zone U-turn NAT

4. Static NAT

The correct answer is: Three zone U-turn NAT

The correct answer involves the concept of Three zone U-turn NAT, which is essential for allowing users on the Inside zone to access a web application using its public IP address while ensuring that the traffic is properly managed across multiple zones, particularly when communication is required between internal clients and external servers. Three zone U-turn NAT is particularly effective when the source of the traffic (in this case, users in the Inside zone) needs to access a resource that is being presented to them by its public IP address. Normally, if a user tries to reach a public IP address from the Inside zone, the firewall would perform Destination NAT to redirect that traffic. However, because the traffic is destined for a service that is, in reality, located internally, the U-turn configuration allows the firewall to recognize this scenario and loop the traffic back into the internal network. By implementing Three zone U-turn NAT, the firewall can effectively translate the public IP address back into its corresponding private IP address so that users can seamlessly access the web application without any unnecessary complications or failed requests. This configuration ensures that routing is optimized and that the users experience consistent access to applications that might otherwise be complicated by NAT traversal issues. While other NAT rule configurations, such as Source NAT and Static NAT, serve