Configuring Azure DNS involves setting up a hosting service for DNS domains that provides name resolution using Microsoft Azure’s global infrastructure. In the context of the Azure Administrator Associate certification, this primarily revolves around managing Public DNS Zones and Private DNS Zones …Configuring Azure DNS involves setting up a hosting service for DNS domains that provides name resolution using Microsoft Azure’s global infrastructure. In the context of the Azure Administrator Associate certification, this primarily revolves around managing Public DNS Zones and Private DNS Zones to ensure connectivity.
To configure a Public DNS Zone, you create a resource for your domain (e.g., contoso.com) within the Azure Portal. Azure assigns name servers to this zone. You must then configure delegation by updating the records at your domain registrar to point to these Azure name servers. Once delegated, you manage standard record sets (A, AAAA, CNAME, MX) to resolve internet queries to your public Azure resources.
For internal networking, you configure Azure Private DNS Zones. This feature provides a reliable, secure DNS service to manage and resolve domain names in a Virtual Network (VNet) without needing to add a custom DNS solution. You create a private zone (e.g., private.contoso.com) and link it to your VNets. A critical configuration option here is 'Auto-registration.' When enabled on a VNet link, virtual machines deployed in that VNet automatically create and update their DNS records in the private zone, drastically reducing manual administrative overhead.
Additionally, Azure DNS supports Alias Record Sets, which allow you to refer to a specific Azure resource (like a Public IP or Traffic Manager profile) seamlessly. If the underlying IP of the resource changes, the DNS record updates automatically. Security is managed via Azure Resource Manager (ARM), allowing you to apply Role-Based Access Control (RBAC) to restrict who can create or modify these DNS records.
Mastering Azure DNS for AZ-104: Implement and Manage Virtual Networking
Overview: Why is Azure DNS Important? In the context of the AZ-104 exam and real-world administration, DNS (Domain Name System) is the fundamental mechanism that translates human-readable domain names (like www.contoso.com) into IP addresses. Azure DNS is critical because it provides a native, highly available, and secure way to manage your DNS records without needing to maintain custom DNS servers. It integrates seamlessly with other Azure services, allowing for automatic updating of records and private name resolution within your Virtual Networks (VNets).
What is Azure DNS? Azure DNS is a hosting service for DNS domains that provides name resolution using Microsoft Azure infrastructure. It allows you to manage your DNS records using the same credentials, APIs, tools, and billing as your other Azure services.
Crucial Distinction for the Exam: Azure DNS is a hosting service for DNS zones. It is not a domain registrar. You cannot buy domain names directly through Azure DNS; you must purchase the domain from a third-party registrar (like GoDaddy) or Azure App Service Domains, then delegate the domain to Azure DNS for management.
How Azure DNS Works Azure DNS operates through two primary types of zones:
1. Public DNS Zones: These are used to resolve domain names to public IP addresses accessible from the internet. When you create a public zone, Azure provides four name servers. You must update the NS (Name Server) records at your domain registrar to point to these Azure name servers to delegate authority.
2. Azure Private DNS Zones: This feature provides a reliable, secure DNS service to manage and resolve domain names in a virtual network without the need to add a custom DNS solution. This allows you to use your own domain names rather than the Azure-provided names. It works strictly within your internal network.
Key Features: - Automatic Registration: When enabled on a VNet link, Virtual Machines created in that VNet automatically have their A-records added to the Private DNS Zone. - Alias Records: These allow you to point a DNS record set specifically to an Azure resource (like a Public IP address or Traffic Manager profile). Crucially, Alias records allow you to use a dynamic IP at the Zone Apex (root domain), which is not possible with standard CNAME records.
How to Answer Questions on Configuring Azure DNS When faced with AZ-104 scenario questions, follow this logic flow:
1. Identify the Scope: Does the scenario require name resolution over the internet (Public IP) or strictly between Virtual Machines in a VNet (Private IP)? If it is internal, choose Azure Private DNS.
2. Check for Custom Domain Requirements: If the question asks to use a specific internal name (e.g., internal.corp) across peered VNets, you must configure a Private DNS Zone and link it to all relevant VNets.
3. Look for 'Auto-Update' Requirements: If the requirement states that creating a new VM should automatically update DNS records to minimize administrative effort, you must select 'Enable auto-registration' when creating the Virtual Network Link to the Private DNS zone.
4. Zone Apex Scenarios: If a question asks how to map the root domain (e.g., contoso.com) to an Azure resource, look for the Alias Record. Standard CNAME records cannot be used at the root level.
Exam Tips: Answering Questions on Configure Azure DNS
Tip 1: Split-Horizon DNS The exam may ask about 'Split-Horizon' setups. This is where the same domain name (e.g., contoso.com) resolves to different IPs depending on where the query originates (internal vs. external). To achieve this in Azure, you utilize a Public DNS Zone and a Private DNS Zone with the exact same name. The Private zone takes precedence for queries originating from within the linked VNet.
Tip 2: Delegation Validity Remember that creating a Zone in Azure does not make it live. You must update the NS records at the domain registrar. If a question involves a site not resolving after setup, check if the Delegation step was performed.
Tip 3: CNAME vs. A Record Use an A Record to map a name to an IP address. Use a CNAME to map a name to another name (like mapping 'www' to 'server1.azurewebsites.net'). Remember: CNAMEs cannot exist at the root/apex; use Alias records there.
Tip 4: Moving Resources You can move DNS zones between resource groups or subscriptions. However, if you delete a resource group, all DNS zones inside it are deleted, and resolution will fail immediately.