Azure Virtual WAN Private Link Scenarios

Introduction

Azure Virtual WAN (vWAN) combined with Azure Private Link offers a powerful and secure way to connect your on-premises networks and remote users to private endpoints of Azure services without traversing the public internet. This document explores various scenarios where this combination can significantly enhance your network architecture, providing secure, reliable, and scalable access to your cloud resources.

Private Link enables you to access Azure PaaS services (like Azure Storage, Azure SQL Database, Azure Key Vault) and your own Azure services hosted in your virtual networks (VNets) over a private endpoint. Virtual WAN acts as a global transit network, simplifying the connectivity between your on-premises sites, remote users, and Azure VNets where these private endpoints reside.

Scenario 1: Remote Work Access

Overview

This scenario focuses on providing secure and direct access for remote users (e.g., employees working from home) to specific Azure services and applications without exposing them to the public internet. Users connect to their closest Virtual WAN hub, and traffic is then routed privately to the target services via Private Link.

Components

• Azure Virtual WAN: Central network hub providing global connectivity.
• Virtual WAN Hubs: Deployed in multiple Azure regions.
• Azure VPN Gateway (in VNet) or Azure Virtual WAN VPN Site: For user VPN connectivity.
• Azure Firewall or Network Security Groups (NSGs): For traffic filtering.
• Private Endpoint: Deployed in a VNet connected to a Virtual WAN hub, establishing a private IP address for an Azure service.
• Azure Service: The target Azure PaaS service (e.g., Azure Storage, Azure SQL DB).
• Azure VPN Client: Installed on remote user devices.

Implementation Steps

1. Set up an Azure Virtual WAN and deploy hubs in relevant regions.
2. Configure a VPN site within Virtual WAN or deploy an Azure VPN Gateway in a VNet that is peered with a Virtual WAN hub.
3. Create a VPN profile for the Azure VPN Client and distribute it to remote users.
4. Deploy the target Azure service (e.g., Azure Storage account).
5. Create a Private Endpoint for the Azure service in a VNet. Ensure this VNet is connected to a Virtual WAN hub.
6. Configure routing within Virtual WAN to ensure traffic from the VPN gateway can reach the VNet hosting the Private Endpoint.
7. Users establish a VPN connection, and their traffic to the Azure service is routed privately through the Virtual WAN hub to the Private Endpoint.

Scenario 2: On-Premises Application Access

Overview

This scenario allows your on-premises applications to securely connect to Azure services via private endpoints. Instead of using public endpoints, traffic travels over a Site-to-Site (S2S) VPN or ExpressRoute connection directly to the Virtual WAN hub, then privately to the Private Endpoint.

Components

• Azure Virtual WAN: Global transit network.
• Virtual WAN Hubs: Deployed in Azure regions.
• Azure VPN Gateway (in VNet) or Azure Virtual WAN VPN Site: For S2S VPN connectivity.
• ExpressRoute Circuit (Optional): For dedicated, high-throughput connectivity.
• On-Premises Network: Containing your applications and network edge devices (VPN/router).
• Private Endpoint: In an Azure VNet connected to a Virtual WAN hub.
• Azure Service: The target Azure PaaS service.

Implementation Steps

1. Deploy Azure Virtual WAN and Virtual WAN hubs.
2. Configure S2S VPN connections or an ExpressRoute circuit between your on-premises network and the Virtual WAN hubs.
3. Deploy the Azure service and create a Private Endpoint for it in a VNet connected to a Virtual WAN hub.
4. Ensure your on-premises network has routes pointing to the Virtual WAN hub for accessing the Azure service's private IP.
5. Configure routing in Virtual WAN to direct traffic from the on-premises connection to the VNet with the Private Endpoint.
6. On-premises applications can now access the Azure service using its private IP address.

Scenario 3: Multi-Region Application Access

Overview

For applications deployed across multiple Azure regions, Virtual WAN provides a global backbone. Private Link ensures that traffic to these services within each region stays private. This scenario demonstrates how users or on-premises sites can access a highly available application spread across multiple Azure regions via Private Link and Virtual WAN.

Components

• Azure Virtual WAN: Global transit network connecting multiple regions.
• Virtual WAN Hubs: Deployed in each Azure region where your application resides or where users/sites connect.
• Site-to-Site VPNs or ExpressRoute: Connecting on-premises sites to the closest hub.
• Remote User VPNs: Connecting remote users to the closest hub.
• Private Endpoints: Deployed in VNets in each region where your application's backend services are hosted.
• Multi-region Azure Services: Your application's backend services (e.g., Azure SQL DB in multiple regions, Azure Kubernetes Service).
• Azure Traffic Manager or Azure Front Door: For global load balancing and failover.

Implementation Steps

1. Set up Azure Virtual WAN with hubs in all relevant regions.
2. Establish S2S VPNs or ExpressRoute circuits from on-premises to the nearest hubs, and configure remote user VPNs.
3. Deploy your Azure services across multiple regions.
4. In each region, create a VNet connected to the local Virtual WAN hub.
5. Deploy Private Endpoints for your Azure services in these VNets.
6. Configure routing in Virtual WAN to ensure seamless connectivity between regions and to the private endpoints.
7. Use Azure Traffic Manager or Front Door to direct users/sites to the closest or healthiest instance of your application, leveraging the private endpoints for data access.

Considerations

• DNS Resolution: Correct DNS configuration is critical for Private Link to resolve service FQDNs to private IP addresses. Consider using Azure Private DNS Zones.
• Routing: Carefully plan your Virtual WAN routing to ensure traffic flows efficiently between your connected sites, users, and private endpoints.
• Security Policies: Implement Azure Firewall or NSGs to control traffic flow and enforce security policies.
• Performance: For high-bandwidth, low-latency requirements, consider ExpressRoute.
• Cost: Understand the pricing models for Virtual WAN, VPN Gateways, Private Link, and data transfer.
• Scalability: Virtual WAN and Private Link are designed to be scalable, but consider the capacity of your Virtual WAN hubs and VPN gateways.

Next Steps

Explore the following resources to deepen your understanding and implement these scenarios:

• Azure Virtual WAN documentation
• Azure Private Link documentation
• Tutorial: Create a Private Endpoint
• Azure Virtual WAN VPN Quickstarts