Azure Virtual Networks

Azure Virtual Network Service Endpoints: Basics

Azure Virtual Network (VNet) service endpoints extend your private network address space and identity to Azure services. Service endpoints enable you to select specific Azure services, such as Azure Storage and Azure SQL Database, and tightly secure them to your VNets. When you enable service endpoints for a service, traffic from your VNet to that service travels over the Azure backbone network, not the public internet.

What are Service Endpoints?

Service endpoints provide a direct, secure, and optimized connection from your Azure Virtual Network to supported Azure platform services. They allow you to:

  • Secure Azure Services: Restrict access to Azure services to only your virtual network. This significantly enhances the security posture of your applications by preventing data exfiltration.
  • Keep Traffic on Azure Backbone: Traffic between your VNet and the Azure service remains on the Azure backbone network, eliminating exposure to the public internet.
  • Simplified Networking: Reduce the complexity of managing network security. You don't need to manage public IP addresses or complex firewall rules for accessing these services.
  • High Availability and Scalability: Leverage the inherent high availability and scalability of Azure services.

How Service Endpoints Work

When you enable a service endpoint for a particular Azure service on a subnet within your VNet, traffic from that subnet destined for the service is automatically redirected over the Azure backbone. The service endpoint effectively extends the identity of your VNet to the Azure service. This allows you to configure access rules for the Azure service to allow traffic only from specific VNets or subnets.

[Placeholder for a diagram illustrating VNet with Subnet, Service Endpoint, and Azure Service connection]

Imagine a diagram here showing your VNet, a subnet, and a connection to an Azure service (like Storage) being routed directly through the Azure backbone via a service endpoint.

Supported Azure Services

Service endpoints are supported for a growing list of Azure services. Some of the most common include:

  • Azure Storage (Blob Storage, File Storage, Table Storage, Queue Storage)
  • Azure SQL Database
  • Azure Cosmos DB
  • Azure Key Vault
  • Azure Data Lake Store Gen1
  • Azure Service Bus
  • Azure Event Hubs
  • Azure Databricks
  • And more...

Always refer to the official Azure documentation for the most up-to-date list of supported services.

Enabling Service Endpoints

You can enable service endpoints for a subnet through the Azure portal, Azure CLI, Azure PowerShell, or ARM templates. The process typically involves:

  1. Navigating to the subnet configuration within your virtual network.
  2. Selecting the desired Azure service from the "Service endpoints" dropdown.
  3. Saving the changes.

Once enabled, you will need to configure the access policies on the Azure service itself to grant access from your VNet or specific subnets. For example, when configuring an Azure Storage account, you can specify that it only accepts traffic from selected virtual networks.

Key Considerations

  • Subnet Level: Service endpoints are configured at the subnet level.
  • Azure Backbone: Traffic uses the Azure backbone for optimal performance and security.
  • No IP Address Changes: The public IP addresses of the Azure services remain the same. The routing is handled by Azure.
  • Firewall Rules: You still need to configure access control lists (ACLs) or firewall rules on the Azure service to allow traffic from your VNet.
  • Service vs. Private Endpoints: Understand the difference between service endpoints and private endpoints. Private endpoints provide a private IP address within your VNet for the Azure service, offering even tighter network isolation.

Example Scenario

Consider an application hosted in an Azure VM within a VNet. This application needs to access data in an Azure Storage account. By enabling the Microsoft.Storage service endpoint on the subnet containing the VM and configuring the storage account's firewall to allow access from that VNet, you ensure that all traffic from the VM to the storage account travels securely over the Azure backbone, bypassing the public internet.

For more detailed configuration steps and advanced scenarios, please refer to the official Microsoft Azure documentation.