This article is based on reporting originally published on InfoQ and Microsoft’s official Azure blog announcement.
What Is Azure Private Link?
Microsoft announced Azure Private Link as a preview service that gives organizations the ability to connect to Azure Platform as a Service (PaaS) offerings—or their own services hosted in Azure—using a private IP address. All traffic over Azure Private Link traverses Microsoft’s backbone network, meaning it never touches the public internet.
At the time of the preview announcement, supported services included Azure Storage and Azure SQL Database, with additional services planned for future releases.
How Azure Private Link Works
Azure Private Link operates on a provider/consumer model. Both the provider and consumer endpoints are hosted in Azure. The connection lifecycle works as follows:
- The consumer requests a connection to a Private Link–enabled service.
- The provider approves the connection through a consent-based call flow.
- Once approved, all traffic is routed over Microsoft’s private network, isolated from the public internet.
Critically, Azure Private Link connections do not require:
- VPN or ExpressRoute gateways
- Network Address Translation (NAT)
- Public IP addresses
As Yousef Khalidi, Corporate Vice President of Azure Networking, explained at the time of the announcement:
Azure Private Link brings Azure services inside the customer’s private VNet. The service resources can be accessed using the private IP address just like any other resource in the VNet. This significantly simplifies the network configuration by keeping access rules private.
Connecting Your Own Services with Azure Private Link
Beyond connecting to Microsoft PaaS offerings, Azure Private Link also supports connecting your own services to other Azure consumers—without routing traffic over a public interface. This is particularly useful for organizations that need to share services with trading partners or across business units, without exposing those services to the internet.
The traditional alternative—VNet peering—does not scale well when federating across many organizations or subscriptions. Khalidi described the Azure Private Link approach:
Using Azure Private Link, you can run your service completely private in your own VNet behind an Azure Standard Load Balancer, enable it for Azure Private Link, and allow it to be accessed by consumers running in different VNet, subscription, or Azure Active Directory (AD) tenant all using simple clicks and approval call flow. As a service consumer all you will have to do is create a private endpoint in your own VNet and consume the Azure Private Link service completely private without opening your access control lists (ACLs) to any public IP address space.
Key Benefits for DevOps and Platform Teams
Data Exfiltration Protection
By mapping PaaS resources to private IP addresses, Azure Private Link prevents outbound PaaS traffic from moving through the public internet. This allows network and security teams to apply network governance policies and block unauthorized data transfers to external destinations—a concern that is difficult to address when PaaS traffic egresses over public endpoints.
Simplified Network Configuration
Because no public IP addresses, NAT rules, or gateways are needed, the network configuration for accessing PaaS services is substantially simpler. Access control rules remain private and consistent with how you manage any other resource inside a VNet.
Avoiding IP Address Conflicts
Azure Private Link can broker connections across multiple VNets, allowing organizations to use their address space more effectively and avoid IP conflicts that commonly arise when peering networks with overlapping CIDR ranges.
Cross-Tenant Connectivity
The consent-based model supports connectivity across different Azure subscriptions and Azure Active Directory tenants. This makes it practical for service providers and enterprise platform teams to expose internal services to specific consumers without broad network-level access grants.
Services Supported at Preview Launch
At the time of the preview announcement (late 2019), Azure Private Link supported a limited set of regions and the following services:
- Azure Storage
- Azure SQL Database
Microsoft indicated that support for the following services was planned for subsequent months:
- Azure Cosmos DB
- Azure Database for MySQL
- Azure Database for PostgreSQL
- Azure Database for MariaDB
- Azure App Service
- Azure Key Vault
Note: Azure Private Link has since moved beyond preview and expanded significantly in supported services and regions. Consult the official Azure Private Link documentation on Microsoft Learn for the current list of supported services, regional availability, and pricing.
Summary
Azure Private Link is a foundational network security capability for teams building on Azure PaaS. It removes the requirement to expose PaaS service endpoints to the public internet, makes network governance over PaaS traffic practical, and scales better than VNet peering for cross-organization connectivity. For any team working with sensitive workloads on Azure, Private Link should be a standard part of the network architecture review.