2.3.8. 💡 First Principle: Azure DNS and Network Endpoints

First Principle: Azure DNS and network endpoints control how resources are discovered and accessed—DNS translates human-readable names into IP addresses, while endpoints define whether resources are reachable from the public internet or only from within your private network. Together, they form the foundation of accessible yet secure cloud architectures.

Without DNS, users would need to remember IP addresses. Without proper endpoint configuration, sensitive resources might be exposed to the internet when they should be private. Azure provides tools to manage both aspects of network accessibility.

Azure DNS:

• Azure DNS:

  • Description: A hosting service for DNS domains that provides name resolution using Microsoft Azure infrastructure.
  • Use Case: Hosting your domain's DNS records in Azure, enabling integration with other Azure services, and leveraging Azure's global anycast network for fast DNS resolution.
  • Key Features:
    • High availability: Built on Azure's global network of DNS servers.
    • Seamless integration: Manage DNS alongside other Azure resources using the same credentials, billing, and support.
    • Azure Private DNS: Provides name resolution within virtual networks without needing custom DNS solutions.

• Azure Private DNS Zones:

  • Description: Provides DNS resolution within your virtual networks using your own domain names.
  • Use Case: Resolving internal hostnames (e.g., db.internal.contoso.com) within VNets without exposing them publicly.

Public and Private Endpoints:

• Public Endpoints:

  • Description: The default way Azure PaaS services (like Storage, SQL Database) are accessed—over the public internet using a public IP address.
  • Use Case: When resources need to be accessed from anywhere on the internet.
  • Security Consideration: Access can be restricted using firewalls, access keys, and network rules, but traffic still traverses the internet.

• Private Endpoints:

  • Description: A network interface that connects you privately and securely to a service powered by Azure Private Link. The private endpoint uses a private IP address from your VNet, effectively bringing the service into your virtual network.
  • Use Case: Accessing Azure PaaS services (Storage, SQL, Cosmos DB) without data leaving the Microsoft network—eliminating public internet exposure.
  • Key Feature: Traffic between your VNet and the service travels over the Microsoft backbone network, not the public internet.

• Service Endpoints:

  • Description: Extends your VNet's private address space to Azure services, optimizing the route to the service over the Azure backbone.
  • Use Case: Securing traffic to Azure services while keeping them publicly addressable. Simpler than private endpoints but less isolated.

Scenario: A healthcare organization stores patient records in Azure Blob Storage. Regulatory requirements mandate that this data must never traverse the public internet. They need to ensure that access to the storage account is only possible from within their Azure virtual network.

Reflection Question: How does a Private Endpoint differ from a Service Endpoint in securing access to Azure PaaS services, and which would be more appropriate for this healthcare organization's compliance requirements?

💡 Tip: For the AZ-900 exam, remember: Public endpoint = accessible from the internet. Private endpoint = private IP in your VNet, no public exposure. Service endpoint = optimized route over Azure backbone, but service keeps its public IP.