Azure DNS Private Resolver Architecture and Benefits

Azure DNS Private Resolver is a game-changer for companies looking to manage their DNS infrastructure more efficiently. It allows you to resolve private DNS names in your virtual network, making it easier to manage your DNS queries.

With Azure DNS Private Resolver, you can create a private DNS zone in your virtual network, which enables you to resolve private DNS names that are not visible on the public internet. This feature is particularly useful for companies with a large number of virtual networks or those that require a high level of security.

The architecture of Azure DNS Private Resolver is designed to be scalable and highly available, with features like automatic failover and load balancing. This ensures that your DNS queries are always resolved quickly and reliably.

To get started with Azure DNS Private Resolver, you'll want to learn how to create one using Azure PowerShell or the Azure portal. This is a crucial step in setting up your resolver.

You can create an Azure DNS Private Resolver by using Azure PowerShell or Azure portal. To do this, you'll need to follow the steps outlined in the Azure documentation.

Here are the next steps to take after creating your Azure DNS Private Resolver:

Now that you've got a good grasp of Azure DNS Private Resolver, it's time to take your skills to the next level.

To create an Azure DNS Private Resolver, you can use Azure PowerShell or the Azure portal.

Learning how to resolve Azure and on-premises domains using the Azure DNS Private Resolver is a crucial step in getting started.

Azure DNS Private Resolver endpoints and rulesets are also worth exploring.

Setting up DNS failover using private resolvers is a great way to ensure your DNS is always available.

Configuring hybrid DNS using private resolvers can also help you manage your DNS more efficiently.

Here are some key networking capabilities of Azure to consider:

Azure DNS Private Resolver offers a range of benefits that make it an attractive solution for businesses.

Fully managed, Azure DNS Private Resolver provides built-in high availability and zone redundancy, ensuring your DNS system is always up and running.

One of the standout advantages of Azure DNS Private Resolver is its cost reduction capabilities. You can run your DNS system at a fraction of the price of traditional IaaS solutions.

Private access to your Private DNS zones is also a significant benefit, allowing you to conditionally forward to and from on-premises.

Azure DNS Private Resolver is highly scalable, offering high performance per endpoint.

To make the most of Azure DNS Private Resolver, you can use DevOps-friendly tools like Terraform, ARM, or Bicep to build your pipelines.

To create an Azure Private DNS Zone, you need to specify the Resource Group and zone name.

This is a simple configuration, and you can manually add records to the zone.

To enable name resolution for your Private DNS Zone, you need to link it to one or more VNets.

This also gives you the option to enable auto VM registration, which will automatically create A records for your VMs in the zone.

Existing VMs in the VNet will automatically be registered in the zone when you link it.

You can link your zone to multiple VNets and have DNS name resolution between them.

However, you need to specify the FQDN and not just the hostname for your name resolution to work.

In this article, we'll explore the basics of Azure DNS Private Resolver. Here's what you can expect to learn.

We'll start by creating two Virtual Networks (VNets): myvnet and myvnet2. These VNets serve as the foundation for our Azure DNS Private Resolver setup.

An Azure DNS Private Resolver is created in the first VNet, and it's assigned an inbound endpoint at 10.10.4. This allows us to configure the resolver for private DNS resolution.

A DNS forwarding ruleset is created for the private resolver, enabling us to define how DNS queries are handled.

The DNS forwarding ruleset is then linked to the second VNet, which allows the resolver to provide DNS resolution services to this network.

We'll also cover how to add example rules to the DNS forwarding ruleset, which is a crucial step in configuring the resolver for your specific use case.

Here's a brief overview of the steps we'll cover in this article:

Azure DNS Private Zones are a manageable DNS zone within Azure that can be manually added to and linked to a VNet or multiple VNets.

To create an Azure Private DNS Zone, you simply need to provide the Resource Group and the zone name.

An A record can be created in the zone, but to enable name resolution for the Private DNS Zone, you need to link the zone to one or more VNets.

Linking the zone to a VNet also gives you the option to enable auto VM registration, which automatically creates A records for your VMs in the zone.

The DNS Suffix Search list has not changed inside your VMs, so you need to specify the FQDN and not just the hostname for name resolution to work.

Azure Private DNS Zones can be used to enable split horizon name resolution, which is useful for scenarios where you have publicly resolvable domains that return public IP addresses but you may want internal users to resolve a different IP.

To set up split horizon with Azure DNS Private Zones, you can create a private zone for a publicly resolvable domain, add an A record, and link the zone to your VNet without enabling auto-registration.

Before testing resolution of names defined in private zones, make sure the private zone is linked to the VNet where the VM is located.

To make private DNS zones work for VMs in a spoke VNet, you need to link the private zone to the spoke VNet as well, not just the hub VNet.

You can add a rule to resolve an Azure Private DNS zone linked to your virtual network, such as azure.contoso.com.

To do this, you'll need to specify the domain name and the target DNS service.

You can also include a rule to resolve an on-premises zone, like internal.contoso.com.

Alternatively, you can create a wildcard rule to forward unmatched DNS queries to a protective DNS service.

Just be careful to test your forwarding rules and ensure they don't cause DNS resolution issues.

If you include a wildcard rule, make sure the target DNS service can resolve public DNS names, as some Azure services have dependencies on public name resolution.

Azure DNS Private Resolver is designed to keep your data close to home. It doesn't move or store customer data out of the region where the resolver is deployed.

This means you can rest assured that your data is being handled locally, and not being transmitted across the globe.

The Azure DNS Private Resolver requires an Azure Virtual Network, and when you create one inside a virtual network, one or more inbound endpoints are established that can be used as the destination for DNS queries.

A hub and spoke VNet topology in Azure is a common configuration for distributed DNS architecture. In this setup, a private resolver is located in the hub VNet and a ruleset link is established to the spoke VNet.

To use forwarding rules in the hub VNet, you need to create and link another ruleset to the Hub VNet. This is because the hub VNet doesn't use ruleset rules to resolve DNS names, but instead relies on Azure-provided DNS.

DNS resolution in the spoke VNet works differently, as it uses the configured forwarding rule to resolve the domain name azure.contoso.com. This is made possible by the virtual network link from the ruleset to the spoke VNet.

Here's a step-by-step summary of the DNS query process when using an Azure DNS Private Resolver:

In a distributed architecture, a hub and spoke VNet topology in Azure is used, where a private resolver is located in the hub and a ruleset link is established with the spoke VNet.

The hub VNet is configured with address space 10.10.0.0/16, while the spoke VNet has address space 10.11.0.0/16. A private DNS zone azure.contoso.com is linked to the hub VNet.

Resources in the hub VNet automatically resolve DNS records in azure.contoso.com using Azure-provided DNS (168.63.129.16), while the spoke VNet resolves azure.contoso.com using the configured forwarding rule in the linked ruleset.

The hub VNet doesn't use ruleset rules to resolve DNS names, but can use forwarding rules if another ruleset is created and linked to the Hub VNet.

To use forwarding rules in the hub VNet, create and link another ruleset to the Hub VNet.

Here's how the DNS query process works in a distributed architecture:

In a centralized architecture, all DNS traffic from a spoke VNet is sent to the hub VNet. The hub VNet can resolve private DNS zones, including azure.contoso.com, using Azure-provided DNS.

The hub VNet must be linked to the private zone, but must not be linked to a forwarding ruleset with an inbound endpoint forwarding rule. This is to prevent DNS resolution loops.

A private resolver is located in the hub VNet, and resources inside the hub VNet can automatically resolve DNS records in azure.contoso.com using Azure-provided DNS.

The spoke VNet uses a Custom DNS setting of 10.10.0.4, corresponding to the Hub's private resolver inbound endpoint.

In this scenario, the spoke VNet sends all of its DNS traffic to the inbound endpoint in the Hub VNet. Other DNS names are resolved for the spoke VNet according to rules provisioned in a forwarding ruleset, if they exist.

The hub VNet doesn't require an outbound endpoint or ruleset, but if one is provisioned and linked to the hub, both the hub and spoke VNets will use the forwarding rules.

Here's a summary of the key components in a centralized architecture:

Point-to-Site VPNs are a crucial part of Azure networking, allowing secure connections between remote users and your virtual network.

The Azure P2S client will receive the DNS server configured in the VNet containing the VPN gateway, which in this case is the Azure Firewall's IP address, 192.168.1.4.

This means that the VPN client will use the Azure Firewall's IP address for DNS resolution, which is essential for accessing resources within the virtual network.

A test VM deployed in the hub VNet with the IP address 192.168.10.4 is used to verify connectivity and DNS resolution.

The VPN Gateway is transparent to traceroute, making it easier to troubleshoot connectivity issues.

To test domain resolution, you can use a tool like the one mentioned in the article, which shows that the system can successfully get the IP addresses for the hostnames being tested.