AZ-700 Question 46
Single answerYou are an Azure network engineer for a company that has deployed two virtual networks (VNet1 and VNet2) in separate subscriptions. Both VNets currently use the 10.0.0.0/16 address space. The company wants seamless communication between these networks using VNet peering. How should you resolve the issue of overlapping address spaces to successfully implement VNet peering?
- A
Modify the address range of at least one VNet to a non-overlapping prefix before creating the peering relationship.
- B
Deploy separate NAT gateways in both VNets to automatically translate overlapping addresses.
- C
Enable BGP on both VNets so that each network can dynamically learn routes, even with overlapping addresses.
- D
Create a dedicated route table in each VNet that routes overlapping IP ranges to the other VNet.
Show answer and explanation
Correct answer: A
Explanation
When implementing VNet peering, each VNet must have a unique address space. Overlapping address spaces prevent VNet peering from being established. The only valid solution is to alter one or both VNet address ranges to ensure they do not overlap. For more information, see the Azure documentation on VNet peering requirements: https://learn.microsoft.com/azure/virtual-network/virtual-network-peering-overview.
- A. Correct.
Option 1 is correct. Azure VNet peering requires non-overlapping address spaces. You must update the address space of at least one of the VNets so they no longer overlap (e.g., change one network to 10.1.0.0/16). Only then can VNet peering be established successfully.
- B. Incorrect.
Option 2 is incorrect. While NAT gateways can provide outbound internet connectivity with address translation, they do not resolve overlapping address space issues for direct traffic between VNets in a peering scenario.
- C. Incorrect.
Option 3 is incorrect. BGP is not supported within a plain VNet peering context. BGP typically applies to VPN gateways or ExpressRoute connections, and it cannot solve overlapping address spaces for VNet peering.
- D. Incorrect.
Option 4 is incorrect. A route table between VNets with overlapping addresses cannot differentiate front-end from back-end subnets properly. VNet peering requires unique address space ranges, not just custom routes.