Azure Private Link Concepts

Azure Private Link provides a secure and efficient way to access Azure Platform as a Service (PaaS) services and Azure hosted customer-owned/partner services within your Azure Virtual Network. It enables you to establish a private connection from your virtual network to these services without exposing them to the public internet.

What is Azure Private Link?

Azure Private Link utilizes a private endpoint within your virtual network. This private endpoint acts as a network interface that points to a specific service. When you connect to the service through this private endpoint, your traffic stays entirely within the Microsoft Azure network, ensuring enhanced security and compliance.

Key Components

1. Private Endpoint

A private endpoint is the network interface that connects privately and securely to a service. It is created in the context of your virtual network and subnet. Each private endpoint is assigned a private IP address from your virtual network.

IP Address: A private IP address from your VNet's address space.
Network Interface (NIC): A managed NIC associated with the private endpoint.
Subnet Association: Resides within a specific subnet of your virtual network.

2. Private Link Service

A private link service is a new type of Azure Load Balancer that enables you to create your own service that can be consumed through a private endpoint. This is particularly useful for exposing your own applications or services hosted within Azure to other Azure customers privately.

3. Azure PaaS Services

Azure Private Link supports a wide range of Azure PaaS services, including:

Azure Storage (Blob, Files, Queues, Tables)
Azure SQL Database
Azure Synapse Analytics
Azure Cosmos DB
Azure Key Vault
And many more...

For a comprehensive and up-to-date list, refer to the official Azure Private Link documentation.

How it Works

Creation: You create a private endpoint in your virtual network, specifying the target Azure service.
Connection: Azure provisions a private endpoint with a private IP address within your VNet.
DNS Resolution: DNS records are updated (often automatically) to map the service's FQDN (Fully Qualified Domain Name) to the private IP address of your private endpoint.
Traffic Flow: When applications in your VNet access the service using its FQDN, DNS resolution directs the traffic to the private endpoint. The traffic then travels privately across the Azure backbone network to the service.

Important: Traffic accessing the service through a private endpoint bypasses the public internet. This significantly reduces the attack surface and improves security.

Benefits of Azure Private Link

Enhanced Security: Data remains within the Azure network, not exposed to the public internet.
Simplified Network Architecture: Reduces the need for complex network configurations like VPNs or ExpressRoute for accessing Azure services.
Consistent Connectivity: Provides a unified connectivity experience for Azure PaaS and your own private services.
Compliance: Helps meet stringent data residency and security compliance requirements.
Improved Performance: Optimized routing within the Azure network can lead to better latency and throughput.

Use Cases

Accessing Azure Storage privately from an Azure VM or AKS cluster.
Connecting to Azure SQL Database from an on-premises application via an ExpressRoute circuit and a virtual network gateway.
Securing access to Azure Key Vault for sensitive applications.
Exposing your own custom services hosted in Azure to other organizations privately.

Consider using Private Link for any scenario where sensitive data or services need to be accessed privately from within your Azure environment.

Resource Examples

Private Endpoint Configuration Snippet (Conceptual)

                {
                  "name": "myPrivateEndpoint",
                  "type": "Microsoft.Network/privateEndpoints",
                  "location": "eastus",
                  "properties": {
                    "subnet": {
                      "id": "/subscriptions/.../resourceGroups/.../providers/Microsoft.Network/virtualNetworks/.../subnets/default"
                    },
                    "privateLinkServiceConnections": [
                      {
                        "name": "myConnection",
                        "properties": {
                          "privateLinkServiceId": "/subscriptions/.../resourceGroups/.../providers/Microsoft.Network/privateLinkServices/myPaaS.blob.core.windows.net",
                          "groupIds": [ "blob" ]
                        }
                      }
                    ],
                    "manualRequest": {
                      "privateResourceName": "myPaaS.blob.core.windows.net",
                      "requestMessage": "Private Endpoint for Storage Account"
                    }
                  }
                }
            

This conceptual snippet illustrates the key properties involved in creating a private endpoint. Actual configurations may vary based on the specific service and resource.

Next Steps

Explore the following resources to learn how to implement Azure Private Link: