Azure Private Link: Secure Access to Azure Services

Azure Private Link provides the most secure and easiest way to access Azure Platform as a Service (PaaS) and Azure customer-owned/partner services from a virtual network. Private Link fundamentally redefines how services are deployed and consumed across networks.

Traditionally, accessing Azure services involved traversing the public internet or using complex network configurations like VPNs or ExpressRoutes for private connectivity. Azure Private Link simplifies this by bringing Azure services directly into your virtual network via a private endpoint.

What is Azure Private Link?

Azure Private Link is a service that enables you to access Azure PaaS services (e.g., Azure Storage, Azure SQL Database) and Azure hosted customer-owned or partner services over a private endpoint in your virtual network. This ensures that traffic between your virtual network and the service travels entirely over the Microsoft Azure backbone network, eliminating exposure to the public internet.

The core principle is that Azure services are no longer accessed through public endpoints but through dedicated private endpoints provisioned within your Azure virtual network(s).

Key Benefits of Azure Private Link

• Enhanced Security: Eliminates public internet exposure of your data and services. Traffic stays within the Azure backbone.
• Simplified Network Architecture: Reduces the need for complex network configurations like firewalls, NAT, and VPN gateways for service access.
• Consistent Connectivity: Provides a unified private access experience for a wide range of Azure services and your own services.
• Seamless Integration: Works with various Azure networking features like VNet peering and VPN/ExpressRoute.
• Granular Access Control: Leverage Azure Network Security Groups (NSGs) and Private Link access policies for fine-grained control.

How Azure Private Link Works

Azure Private Link uses Azure Private Endpoint to bring Azure services into your virtual network. Here's a simplified overview:

1. Creation of Private Endpoint: You create a private endpoint in your virtual network. This endpoint is assigned a private IP address from your VNet's address space.
2. Service Selection: You select the Azure service you want to connect to (e.g., a specific Azure Storage account).
3. Private IP Assignment: The private endpoint is associated with the selected Azure service. Traffic destined for the service's standard FQDN (e.g., mystorage.blob.core.windows.net) is now resolved to the private IP address of the private endpoint within your VNet.
4. Traffic Routing: When your application in the virtual network attempts to access the service, DNS resolution directs the traffic to the private IP address. The traffic then traverses the Azure backbone network directly to the service, bypassing the public internet.
5. Azure Private Link Service (for own services): For self-hosted or partner services, you can create a Private Link Service. This service is associated with a network load balancer and exposes your service to consumers via their private endpoints.

Common Use Cases

• Securely accessing Azure PaaS services: Connect to Azure Storage, Azure SQL, Azure Cosmos DB, Azure Key Vault, etc., from your virtual networks without exposing them to the internet.
• Connecting on-premises applications to Azure services: Via VPN or ExpressRoute, on-premises applications can leverage Private Link to access Azure services securely.
• Providing secure access to partner services: Partner services can be exposed securely to your virtual network.
• Exposing your own services to Azure consumers: Use Private Link Service to offer your applications running in Azure to other Azure customers privately.
• Meeting compliance requirements: Facilitates compliance with strict data residency and security regulations that prohibit public internet exposure.

Getting Started with Azure Private Link

Implementing Azure Private Link is straightforward. You can configure it through the Azure portal, Azure CLI, Azure PowerShell, or ARM templates.

Key Steps (Azure Portal):

1. Navigate to the Azure service you wish to connect to (e.g., your Storage Account).
2. Under "Networking" or "Security" settings, find "Private endpoint connections".
3. Click "+ Private endpoint".
4. Configure the basics: Subscription, Resource Group, Name, Region.
5. Select the target Azure subscription and resource type.
6. Select the specific Azure service instance.
7. In the "Networking" tab, select the target virtual network and subnet where you want to deploy the private endpoint. You can also configure private DNS integration here.
8. Review and create the private endpoint.

Once the private endpoint is created and approved by the service owner, your application within that virtual network can access the Azure service using its standard FQDN, with all traffic routed privately.