Azure Private Link

Overview

Azure Private Link provides a way to access Azure PaaS Services (like Azure Storage and SQL Database) and Azure hosted customer-owned services over a private endpoint in your virtual network. Traffic between your virtual network and the service travels the Microsoft backbone network, eliminating exposure from the public internet.

This significantly enhances security and compliance for your applications by ensuring that sensitive data remains within your network boundaries.

Key Benefits:

• Data Exfiltration Prevention: Limits the risk of data leakage.
• Simplified Network Architecture: Eliminates the need for complex network security configurations like VPNs or ExpressRoute for service access.
• Private Connectivity: Leverages Azure's high-speed backbone for reliable and secure connections.
• Unified Access: Provides a consistent way to access various Azure services and your own services.

How it Works

Azure Private Link uses Azure Private Endpoint, which is a network interface that connects you privately to a service. The private endpoint uses a private IP address from your virtual network, effectively bringing the service into your virtual network.

1. Service Provider: The Azure service provider (e.g., Azure Storage) exposes their service endpoint.
2. Private Endpoint Creation: You create a Private Endpoint in your virtual network, selecting the target Azure service and specifying a private IP address.
3. DNS Resolution: Azure DNS resolves the service's FQDN (Fully Qualified Domain Name) to the private IP address of the Private Endpoint.
4. Private Connection: When your application requests access to the service, the traffic is routed through your virtual network to the Private Endpoint and then to the service over the Microsoft backbone.

Use Cases

• Accessing Azure SQL Database from an Azure VM without exposing the database to the public internet.
• Connecting to Azure Blob Storage from an on-premises application via a VPN or ExpressRoute to a VNet with a Private Endpoint.
• Securing access to your custom web application hosted on Azure App Service by placing it behind a Private Endpoint.
• Ensuring compliance requirements are met for data handling and access.

Creating a Private Endpoint

You can create a Private Endpoint using the Azure portal, Azure PowerShell, Azure CLI, or ARM templates.

Example using Azure CLI:

az network private-endpoint create \
  --name myPrivateEndpoint \
  --resource-group myResourceGroup \
  --vnet-name myVNet \
  --subnet mySubnet \
  --private-connection-resource-id "/subscriptions/{subscriptionId}/resourceGroups/{rgName}/providers/Microsoft.Storage/storageAccounts/{storageAccountName}" \
  --group-ids "blob" \
  --location "eastus"
                

After creation, you typically need to configure DNS for the Private Endpoint to ensure proper name resolution.

Best Practices

• Use Private Link for all Azure PaaS services that support it, especially for sensitive workloads.
• Implement proper network segmentation and security groups in your virtual network.
• Configure Private DNS Zones for seamless name resolution to private IP addresses.
• Regularly review and audit access logs for services accessed via Private Link.