Q: Your enterprise has 45 spoke VNets across 3 Azure regions, connected via custom VNet peerings and an array of third-party NVA firewall VMs. Route table management is manual, BGP peering is brittle, and transit routing between spoke VNets requires complex UDRs. How do you design and migrate to Azure Virtual WAN with Azure Firewall Premium?
Architectural decision framework and deployment guide for migrating enterprise multi-region networking from traditional custom Hub-Spoke VNet peering to Azure Virtual WAN with secure hub routing.
#Azure #Virtual WAN #Hub-Spoke #Azure Firewall #Routing #ExpressRoute
🎙️ Candidate Opening & Architectural Context
"As our Azure footprint scaled beyond 30 subscriptions, maintaining User-Defined Routes (UDRs) on every spoke subnet to force traffic through hub firewalls became an operational nightmare. We re-architected our global backbone onto Azure Virtual WAN."
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🛠️ Production Runbook & Step-by-Step Resolution
1️⃣
Deploy Azure Virtual WAN & Secure Virtual Hubs
Establish a centralized Microsoft-managed global transit network:
- Virtual WAN Hub Creation: Provisioned Virtual WAN (Standard tier) and created Regional Virtual Hubs in East US, West Europe, and Southeast Asia:
az network vwan create -g rg-net -n vwan-global --type Standard. - Deploy Azure Firewall: Embedded Azure Firewall Premium inside each Virtual Hub with
az network vhub update --name hub-eastus --resource-group rg-net --azure-firewall-id $FW_ID.
Pro Tip: Virtual WAN hubs automate any-to-any mesh routing across Microsoft's global fiber backbone without requiring manual full-mesh VNet peerings.
2️⃣
Configure Routing Intent & Routing Policies
Eliminate manual spoke UDRs by enforcing global routing intent at the hub level:
- Routing Intent Policy: Configured Routing Intent on the hub specifying that all Private Traffic (spoke-to-spoke, spoke-to-onprem) and Internet Traffic must traverse Azure Firewall.
- Automated Route Propagation: Virtual WAN automatically injects 0.0.0.0/0 and RFC 1918 default routes into all connected spoke VNets without manual route table edits.
Pro Tip: Routing Intent eliminates hundreds of manual spoke UDRs, preventing route table drift across decentralized development teams.
3️⃣
Terminate ExpressRoute & Site-to-Site VPN in Virtual Hubs
Connect on-premises data centers and branch offices directly to the nearest regional hub:
- ExpressRoute Gateway: Provisioned 10 Gbps ExpressRoute Gateway inside Hub East US; connected primary enterprise MPLS circuits.
- VPN Gateway Failover: Configured S2S VPN Gateway in active-active mode as secondary automated backup path with dynamic BGP route peering.
Pro Tip: Spoke VNets connected to Hub East US can communicate with branches connected to Hub West Europe over Microsoft's backbone with zero extra transit appliances.
4️⃣
Configure Azure Firewall Premium IDPS & TLS Inspection
Enforce deep packet inspection and threat protection across all transit traffic:
- IDPS Rules: Enabled Intrusion Detection and Prevention System (IDPS) in Alert and Deny mode.
- TLS Decryption: Uploaded enterprise intermediate CA certificate from Azure Key Vault to inspect encrypted outbound HTTPS egress traffic.
Pro Tip: Azure Firewall Premium scales automatically up to 30 Gbps throughput per hub, eliminating manual NVA VM clustering.
💡 The Senior SRE Gold Nugget (Key Architectural Takeaway)
"Azure Virtual WAN replaces complex custom Hub-Spoke VNet peering and manual UDR management with Microsoft-managed automated global transit routing and integrated Azure Firewall security."
⚡ 60-Second Elevator Pitch Talking Points
- Deploy Azure Virtual WAN Standard with regional Virtual Hubs across primary business regions.
- Enforce Hub Routing Intent to automatically steer private and internet traffic through Azure Firewall.
- Eliminate hundreds of manual spoke UDRs and eradicate human route configuration errors.
- Terminate ExpressRoute and VPN gateways in virtual hubs for seamless global transit.
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