How Azure Private Link Works
Azure Private Link provides a secure and private way to access Azure Platform as a Service (PaaS) services, as well as Azure customer-owned services, over a private endpoint within your virtual network. This eliminates exposure to the public internet, enhancing your security posture.
Core Concepts
- Azure Private Endpoint: A network interface that connects you privately and securely to an Azure service. It is assigned a private IP address from your virtual network, effectively bringing the service into your private network.
- Private Link Service: A service that you own and run in your Azure Virtual Network. It enables you to expose your customer-owned services to consumers on other Azure Virtual Networks securely and privately.
- Network Interface (NIC): The Private Endpoint is implemented as a Network Interface (NIC) in your virtual network.
The Workflow
Here's a breakdown of how Azure Private Link facilitates secure access:
Conceptual Diagram:
(Diagram illustrates traffic flowing from a virtual network to a private endpoint, bypassing public internet, to reach an Azure service.)
- Service Provider and Consumer: There's a service provider (e.g., Azure Storage, Azure SQL Database) and a service consumer (your application running in a virtual network).
- Creating a Private Endpoint: The service consumer creates a private endpoint in their virtual network. This private endpoint is associated with a specific Azure service resource (e.g., a specific storage account).
- Private IP Address Assignment: The private endpoint is assigned a private IP address from the consumer's virtual network subnet. This IP address is dedicated to this specific service instance.
- DNS Resolution: When your application attempts to connect to the service using its fully qualified domain name (FQDN), Azure Private DNS zones (or custom DNS servers configured to resolve these records) direct the traffic to the private IP address of the private endpoint.
- Traffic Routing: Traffic destined for the Azure service is now routed directly through the Azure backbone network to the private endpoint. It never traverses the public internet.
- Accessing the Service: The private endpoint acts as the gateway, forwarding the traffic securely to the target Azure service.
Benefits of Azure Private Link
Enhanced Security: Significantly reduces the attack surface by keeping service traffic off the public internet.
- Simplified Network Architecture: No need for complex VNet peering, NAT gateways, or VPNs to access services privately.
- Compliance: Helps meet regulatory and compliance requirements that mandate private access to services.
- Consistent Connectivity: Provides a unified experience for accessing both PaaS services and your own services hosted in Azure.
Scenarios
- Accessing Azure PaaS services like Azure Storage, Azure SQL Database, Azure Cosmos DB, Azure Key Vault, etc., from a virtual network.
- Connecting an on-premises environment to Azure PaaS services through Azure ExpressRoute or VPN Gateway, leveraging Private Link for secure access.
- Enabling secure communication between different virtual networks for custom applications exposed via Private Link Service.
By using Azure Private Link, you can build robust and secure cloud architectures with confidence.