Deploying DNS Private Resolvers and Private DNS Zones for Azure AI Supported Services

Private Networks:

1. Private DNS Zones: Resolves domain names to private IPs within Azure virtual networks without exposing them to the internet. Private DNS Zones are global, you don’t need to create multiple same private DNS Zones, you can reuse the same zones as it’s global
2. DNS Private Resolvers: Fully managed service that enables DNS resolution between Azure VNets and on-premises networks without custom DNS servers. DNS Private resolvers are regional, which means if you have Azure EAST US and WEST US 2 regions, you need to create DNS Private resolvers in both regions linked to Private DNS Zones, you can adopt centralized or distributed DNS Private resolvers, I will discuss both options later in this article

 

Public Networks: <In this part – not focusing on Public Networks>

1. Public DNS Zones: Resolves internet-facing domain names to publicly accessible IP addresses
2. Traffic Managers: DNS-based traffic load balancer that routes client requests to the best available global endpoint
3. DNS Security Policy: Controls and protects DNS resolution behavior (e.g., filtering, forwarding, and access rules) to secure name resolution and prevent misuse

**Note: 1. Follow Prerequisites to deploy resources. 2. A common misconception is that VNet peering enables DNS resolution. In reality, private DNS zones are only accessible to VNets that are explicitly linked to them, peering provides connectivity, but not name resolution.

In the following snapshot à Azure Portal à Network Foundations à DNS, lets explore individual DNS Services offered and later in this document, we will interconnect

 

 

**Credits to Microsoft Azure Portal Design team for creating new grouped views – you can check out for more – like compute infrastructure, Hybrid, Backup

 

Now, let’s delve into scenario 01: I have grabbed the following snapshot from Azure AI Landing Zones and removed non-network Azure resources to focus only on private Network components,

**Credits to AI Landing Zone team for the diagram, Original Version:

 

 

 

1. Inbound Zoom in view with End-to-End Flow

 

 

 

 

*Link Private DNS to DNS resolvers in other regions, Private DNS is GLOBAL and DNS Resolvers are regional

 

Example Snapshot of entire flow:

1. Nslookup from Client machine,

 

 

 

2. Domain – DNS Conditional Forwarder configuration

 

 

 

 

 

Note 1: Make sure you selected “All DNS Servers in this forest” for replication, otherwise users pointed to some other domain will be unable to resolve

 

 

 

 

 

 

 

Verifying Connectivity with PsPing <credit to Sysinternals team PsPing  >

PsPing, a tool from Sysinternals, is highly effective for verifying network connectivity from on-premises environments to Azure resources on specific ports. This is particularly useful when you need to ensure connectivity to ports such as 445, 443, 1433, 1521, or any other port required by Azure services you intend to access from either on-premises locations or other cloud environments.

By using PsPing, you can test and confirm that the necessary ports are open and accessible, which is crucial for troubleshooting connectivity issues and ensuring smooth communication between your on-premises infrastructure and Azure-hosted resources.

 

 

 

 

 

 

 

3. Ensure your firewall is set to allow traffic
4. DNS private resolvers – inbound configuration

 

 

 

5. Private DNS Configuration

 

 

 

Virtual Network links enable to your private dns

 

 

 

 

6. Make sure you have peer between hub and spoke
7. Private Endpoint configuration

 

 

8. Storage Account configuration

 

 

 

 

“Replace the file share with any supported Azure service that uses Private Endpoints, and follow the same guidance.”

 

 2. Outbound <flow and resources colored with blue> part 2 upcoming soon