Azure DNS: Domain Name System

Azure DNS is a hosting service for DNS domains that provides name resolution using Microsoft Azure. By hosting your domains in Azure, you can manage your DNS records using the same credentials, APIs, and billing tools that you use for your other Azure services.

Key Features and Concepts

Zone Files

Azure DNS zones are used to host the DNS records for a domain. A DNS zone is identified by its domain name. For example, the domain name contoso.com represents a DNS zone.

Record Sets

Within a DNS zone, DNS records are organized into record sets. A record set contains DNS records of the same type and with the same name. For example, you might have an A record set for www.contoso.com and another MX record set for contoso.com.

Supported Record Types

Azure DNS supports the following common DNS record types:

A: Maps a hostname to an IPv4 address.
AAAA: Maps a hostname to an IPv6 address.
CNAME: Maps a hostname to another hostname.
MX: Specifies the mail servers responsible for accepting email for the domain.
NS: Specifies the name servers for the domain.
PTR: Maps an IP address to a hostname (used for reverse DNS lookups).
SRV: Specifies the location of hosts that provide specific services.
TXT: Allows administrators to embed text in a DNS record.
SOA: Start of Authority, provides authoritative information about a DNS zone.

High Availability and Resilience

Azure DNS is built on Azure infrastructure, providing high availability and resilience. Your DNS zones are distributed across multiple Azure name servers, ensuring that your domain remains resolvable even if one name server is unavailable.

Use Cases

Hosting public DNS domains: Manage your domain's public DNS records directly within Azure.
Private DNS zones: Provide name resolution for virtual machines and other resources within an Azure virtual network without requiring custom DNS solutions.
Integrating with Azure services: Easily point Azure resources like App Services, Virtual Machines, and Load Balancers to your DNS records.
Traffic management: Use Azure DNS in conjunction with Azure Traffic Manager for advanced traffic routing strategies.

Getting Started

Create a DNS Zone

You can create a DNS zone using the Azure portal, Azure CLI, or Azure PowerShell.

Example using Azure CLI:

az network dns zone create \
    --resource-group myResourceGroup \
    --name contoso.com

Add DNS Records

Once a zone is created, you can add record sets to it.

Example using Azure CLI to add an A record:

az network dns record-set a add-record \
    --resource-group myResourceGroup \
    --zone-name contoso.com \
    --record-set-name www \
    --ipv4-address 203.0.113.10

Note: After creating your DNS zone in Azure, you must update your domain registrar's name server (NS) records to point to the Azure DNS name servers provided for your zone. This delegates DNS management for your domain to Azure.

Private DNS Zones

Azure Private DNS zones allow you to use custom domain names in your virtual networks without needing to create and manage a custom DNS solution. These zones are linked to virtual networks and are only resolvable from within those networks.

Benefits of Private DNS Zones

Automatic registration of DNS records for virtual machines deployed in linked virtual networks.
Resolution of private IP addresses without using custom DNS servers.
Integration with Azure services.

Tip: For high-traffic applications, consider using Azure DNS in combination with Azure Traffic Manager to distribute traffic across multiple regions and improve availability.

Pricing

Azure DNS pricing is based on the number of DNS zones hosted and the number of DNS queries received. For detailed pricing information, please refer to the Azure DNS pricing page.

Important: Ensure that you correctly configure your NS records at your domain registrar to delegate your domain to Azure DNS. Incorrect configuration will lead to your domain not being resolvable.