Azure Private Link is a networking service that allows applications in an Azure Virtual Network to access supported Azure services and private services through a private IP address, without sending application traffic over the public internet. The traffic remains on Microsoft's backbone network.
How Azure Private Link Works
The key component is the Private Endpoint. It is a network interface created inside your virtual network and assigned a private IP address. That endpoint can connect to services such as Azure Storage, Azure SQL Database, Azure Cosmos DB, or a service published through Azure Private Link Service.
A simplified flow looks like:
Application → Private Endpoint → Azure Private Link → Target Service
For example, instead of an application accessing a database through its public endpoint, you can place a private endpoint in the application's VNet and route the connection through that private address.
Why Is Private Link Important?
The biggest advantage is private connectivity and reduced public exposure. Private Link allows organizations to keep service traffic away from the public internet and can be used from Azure VNets, peered networks, and on-premises environments connected through VPN or ExpressRoute.
It also provides more granular access because a private endpoint maps to a specific private-link resource rather than giving broad access to an entire service. This can help reduce the risk of unintended resource access and data exfiltration.
Private Endpoint vs. Private Link Service
These two concepts are easy to confuse:
- Private Endpoint: Used by a consumer to privately access a supported service.
- Private Link Service: Used by a service provider to expose its own service privately to consumers. The service is typically placed behind an Azure Standard Load Balancer.
So, if your application simply needs private access to Azure Storage or Azure SQL, you will typically work with a Private Endpoint. If your organization provides a service that other customers or teams need to consume privately, Private Link Service becomes relevant.
DNS Is a Critical Part
Creating a private endpoint is not the end of the configuration. DNS resolution must also be designed correctly. The service's fully qualified domain name needs to resolve to the private endpoint's IP address. Azure Private DNS zones are commonly used for this purpose.
Many connectivity problems that appear to be networking issues are actually caused by incorrect DNS configuration.
Private Link vs. Service Endpoints
A useful distinction is that a service endpoint keeps the service publicly routable, whereas a private endpoint provides a private IP inside your VNet and enables private connectivity to the specific resource.
For security-sensitive architectures, Private Link is therefore useful when reducing public network exposure is an important requirement.
Practical Considerations
Before deploying Private Link at scale, engineers should plan:
- Private DNS and name resolution
- VNet and subnet design
- NSG and routing requirements
- RBAC and connection approval
- Monitoring and logging
- Public network access settings
- Disaster recovery and multi-region connectivity
Microsoft also recommends disabling public network access on the target resource after private connectivity has been validated when the architecture requires traffic to flow exclusively through private endpoints.
Final Thoughts
Azure Private Link is more than simply assigning a private IP to an Azure service. It provides a controlled private connectivity model that helps organizations build secure, segmented, and scalable cloud architectures.
For DevOps and cloud engineers, understanding Private Link is especially important when designing production environments where databases, storage, APIs, and internal services should not depend on public internet connectivity.