Azure SQL Database Networking

This document provides a comprehensive overview of networking concepts and configurations for Azure SQL Database. Understanding how to secure and manage network access to your Azure SQL Database is crucial for data protection and performance.

Key Considerations

Network security is a multi-layered approach. This article will cover firewalls, virtual networks, private endpoints, and service endpoints to help you build a robust network security strategy.

Understanding Azure SQL Database Network Security

Azure SQL Database offers several features to control network access. These include:

  • Firewall Rules: At the server and database level, allowing or denying access from specific IP addresses or ranges.
  • Virtual Network Service Endpoints: Extending your Azure Virtual Network (VNet) to the Azure SQL Database service, allowing you to restrict connectivity to only resources within your VNet.
  • Private Endpoints: Providing a dedicated IP address from your VNet to Azure SQL Database, enabling private connectivity over the Azure backbone.
  • Managed Virtual Network: A dedicated virtual network for Azure services like Azure SQL Database, offering enhanced security and isolation.

Configuring Firewall Rules

Firewall rules are the most basic form of network security. You can configure them at both the server and database levels.

Server-Level Firewall Rules

These rules apply to all databases on the Azure SQL Database server. You can set them via the Azure portal, PowerShell, or Azure CLI.

# Example Azure CLI command
az sql server firewall-rule create --resource-group <your-resource-group> --server <your-server-name> --name "AllowMyIP" --start-ip-address "203.0.113.1" --end-ip-address "203.0.113.1"

Database-Level Firewall Rules

These rules apply to a specific database and can override server-level rules if needed. They are less commonly used but offer granular control.

Virtual Network Integration

Leveraging virtual networks enhances security by keeping traffic within the Azure network and away from the public internet.

Service Endpoints

When you enable VNet service endpoints for Azure SQL Database, traffic from your VNet to the SQL Database service travels over the Azure backbone, not the public internet. You can then configure VNet rules to allow access from your subnet.

Azure SQL Database VNet Service Endpoint Diagram

Private Endpoints

A private endpoint assigns a network interface with a private IP address from your VNet to Azure SQL Database. This ensures that all traffic to the database uses this private IP, making it inaccessible from the public internet.

Benefit of Private Endpoints

Private endpoints offer the highest level of network isolation, ensuring that your Azure SQL Database can only be accessed from within your defined virtual network or connected on-premises networks.

Choosing the Right Network Configuration

The best network configuration depends on your specific security requirements and architecture:

  • Basic Security: Server and database firewall rules are sufficient for simple applications or testing.
  • Enhanced Security: VNet service endpoints are ideal when you want to allow access from specific subnets within your VNet while keeping traffic on the Azure backbone.
  • Maximum Security & Isolation: Private endpoints are recommended for sensitive data or when you need to completely isolate your database from the public internet.

Further Reading