Step-by-Step demonstration on Azure Private Link implementation

Azure Private Link enables secure, private connectivity from your virtual network (VNet) to Azure services or your own services.

Private Link uses a Private Endpoint, which is a private IP address within your VNet, to establish the connection.

Below are the detailed steps to implement Azure Private Link.

Step 1: Prerequisites

Before implementing Private Link, ensure the following:

1. Virtual Network

A VNet with a subnet where the Private Endpoint will be deployed.

2. Azure Service

Identify the Azure service (e.g., Azure Storage, SQL Database) or your custom service to connect.

3. Access Control

Ensure you have the necessary permissions to configure both the VNet and the Azure service.

Step 2: Create a Private Endpoint

A Private Endpoint is a network interface in your VNet that uses a private IP to connect to a specific Azure service or resource.

Steps to Create a Private Endpoint:

1. Navigate to Azure Portal

• Go to the Azure service (e.g., Storage Account) that you want to connect.

2. Select Networking

• Open the Networking settings of the Azure service.

• Locate the Private Endpoint connections section.

3. Add Private Endpoint

• Click + Private Endpoint and fill in the following details:

  • Name: Enter a descriptive name for the Private Endpoint.

  • Region: Select the region of the Azure service.

  • Resource type and name: Choose the type of Azure service and the specific resource to connect.

  • Connection method: Choose Private Link.

4. Select VNet and Subnet

• Choose the VNet and subnet where the Private Endpoint will reside. Ensure the subnet has no overlapping IP ranges with the service's region.

5. Integrate DNS

• Enable Private DNS Integration if using Azure's Private DNS Zones for automatic name resolution.

6. Review and Create

• Review your configuration and click Create.

Step 3: Configure the Azure Service

After creating the Private Endpoint, configure the Azure service to allow traffic only through Private Link.

Example Configuration for Azure Storage:

1. Restrict Public Access

• Go to the Networking section of your Storage Account.

• Under Firewalls and Virtual Networks, select Disable public access or allow access only through private endpoints.

2. Add the Private Endpoint

• Confirm that the newly created Private Endpoint is listed under Private Endpoint connections.

Step 4: Configure DNS

To ensure smooth connectivity, configure DNS so that requests to the Azure service resolve to the Private Endpoint's private IP.

DNS Configuration Options:

1. Azure Private DNS Zone (Recommended)

• If you enabled Private DNS during the Private Endpoint creation, Azure will automatically create and associate a Private DNS Zone (e.g., privatelink.blob.core.windows.net) with the VNet.

2. Custom DNS Server

• If using custom DNS servers, add a DNS record that points the service's public domain name to the Private Endpoint's private IP.

3. Test DNS Resolution

• From a VM in the VNet, run nslookup <Azure service name> to ensure it resolves to the private IP.

Step 5: Validate the Configuration

1. Deploy a Test VM

Create a VM in the same VNet as the Private Endpoint or in a peered VNet.

2. Test Access

Try accessing the Azure service (e.g., upload/download data to/from a Storage Account, connect to an SQL Database).

3. Verify Private Connectivity

Use tools like traceroute or Wireshark to confirm that traffic is routed via the private IP.

Example: Private Link for Azure SQL Database

Scenario

You want to connect an application in a VNet to an Azure SQL Database securely using Private Link.

1. Create a Private Endpoint

• Go to the SQL Server resource (not the database).

• Open Private Endpoint connections → Add Private Endpoint.

• Select the SQL Server and database, VNet, and subnet.

2. Configure DNS

• Enable Private DNS Zone for privatelink.database.windows.net.

• Ensure your application can resolve the SQL Server's name to the Private Endpoint's private IP.

3. Restrict Public Access

• Go to the SQL Server firewall settings and disable access via public networks.

4. Test Connection

• From a VM in the VNet, connect to the database using its private IP or DNS name.

Key Considerations

1. Subnet Policies

The subnet where the Private Endpoint is deployed should not have a Network Security Group (NSG) blocking Private Link traffic.

2. VNet Peering

If accessing the Private Endpoint from a different VNet, ensure VNet peering is configured, and DNS settings propagate correctly.

3. Cross-Region Access

Private Link supports cross-region access. Ensure DNS resolves correctly for multi-region deployments.

4. Monitoring

Use Azure Monitor and Network Watcher to track and troubleshoot Private Link traffic.

Advantages of Private Link

1. Higher Security

No exposure to the internet; all traffic flows privately within Azure's backbone network.

2. Resource-Level Control

Access is restricted to specific Azure resources, unlike Service Endpoints which apply at the service level.

3. On-Premises Support

Works seamlessly with VPN or ExpressRoute for private access from on-premises.

Summary

Implementing Azure Private Link provides a secure and private way to connect to Azure services and your own applications.

By creating Private Endpoints, restricting public access, and ensuring proper DNS resolution, you can enhance the security and performance of your Azure resources.