Azure DNS Configuration

This document provides comprehensive guidance on configuring Azure DNS to manage your domain names effectively. We will cover key configuration aspects, including creating DNS zones, managing record sets, and leveraging advanced features for optimal performance and reliability.

Creating and Managing DNS Zones

A DNS zone in Azure DNS hosts the DNS records for your domain. You can create a public DNS zone for domains that are resolvable on the internet or a private DNS zone for use within your virtual networks.

Public DNS Zones

To create a public DNS zone:

  1. Navigate to the Azure portal.
  2. Search for "DNS zones" and select it.
  3. Click "Create" to start the wizard.
  4. Provide a Resource Group, Name (your domain name, e.g., contoso.com), and select "Public" for the Zone type.
  5. Click "Review + create" and then "Create".

Private DNS Zones

Private DNS zones are linked to specific virtual networks and are used for internal name resolution.

  1. Follow steps 1-3 above for creating a DNS zone.
  2. For the Zone type, select "Private".
  3. Specify the Virtual Network links for the zone.
  4. Enter a Resource Group and Name (your internal domain name).
  5. Click "Review + create" and then "Create".
Note: When creating a public DNS zone, Azure provides 4 name servers that you will need to delegate your domain to at your domain registrar.

Configuring DNS Record Sets

Within a DNS zone, you create record sets to map domain names to IP addresses or other resources. Azure DNS supports various record types, including A, AAAA, CNAME, MX, SRV, TXT, and PTR.

Adding a New Record Set

  1. Open your DNS zone in the Azure portal.
  2. Click "+ Record set" at the top of the zone's overview page.
  3. Enter the Name (subdomain, or leave blank for the root domain).
  4. Select the Type (e.g., A, CNAME).
  5. For an 'A' record, enter the IPv4 address. For a 'CNAME' record, enter the alias.
  6. Set the TTL (Time To Live) for the record.
  7. Click "OK" to create the record set.
Important: The TTL value determines how long DNS resolvers cache your record. Lower TTLs allow for faster propagation of changes but can increase DNS query load.

Advanced Configuration Options

Azure DNS offers several advanced features to enhance your DNS management capabilities.

Alias Records

Alias records are an Azure-specific feature that can point to an Azure resource, such as a public IP address, Azure Traffic Manager profile, or another Azure DNS zone. This provides a more integrated experience for managing DNS for Azure resources.

Tip: Use alias records when pointing to Azure resources to automatically update your DNS records if the underlying resource's IP address changes.

Traffic Management Integration

Azure DNS integrates seamlessly with Azure Traffic Manager. You can create Traffic Manager profiles to distribute traffic across multiple endpoints for high availability and performance, and then point your Azure DNS records to these profiles using alias records.

DNSSEC (DNS Security Extensions)

While Azure DNS does not directly support DNSSEC configuration within its portal, you can use Azure DNS with third-party DNSSEC signing services to protect your zones from cache poisoning and other threats. You will need to manage your DS records at your domain registrar.

Using the Azure CLI for Configuration

You can also configure Azure DNS using the Azure Command-Line Interface (CLI) for scripting and automation.

Example: Creating a new A record


az network dns record-set a add-record \
  --resource-group MyResourceGroup \
  --zone-name contoso.com \
  --record-set-name www \
  --ipv4-address 203.0.113.5

Example: Creating a CNAME record


az network dns record-set cname set-record \
  --resource-group MyResourceGroup \
  --zone-name contoso.com \
  --record-set-name mail \
  --cname alias.contoso.net
Warning: Always test your DNS changes thoroughly after deployment to ensure they are resolving correctly and that no unintended side effects occur.

Common Issues and Solutions