Azure Firewall is a cloud-native network security service that protects your Azure virtual network resources. It is a fully stateful firewall as a service with built-in high availability and unrestricted cloud scalability. However, some Azure Firewall customers may face challenges when they need to configure non-RFC-1918 address spaces to not SNAT through the Azure Firewall. This can cause issues with routing, connectivity, and performance. To address this problem, Azure Firewall has introduced a new feature that allows customers to specify which address spaces should not be SNATed by the firewall. This feature can help customers reduce the overhead of managing custom routes and NAT rules and improve the efficiency and reliability of their network traffic. In this blog, we will explain how the feature works, what Azure Route Server is, and how to enable it. We will also provide a QuickStart guide and some examples to help you get started with this feature.