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Azure DNS

Definition

Azure DNS is a cloud-based Domain Name System (DNS) service provided by Microsoft Azure. It allows you to host your DNS domains alongside your Azure resources, enabling you to manage DNS records using the same credentials, APIs, tools, and billing as your other Azure services.

Key Features

  1. Global Reach:

    • Azure DNS uses a global network of name servers to provide fast DNS responses and high availability.
    • DNS queries are answered from the closest DNS server to the end user.

  2. DNS Zones:

    • Host your DNS domain in Azure DNS by creating a DNS zone.
    • A DNS zone is used to manage the DNS records for a specific domain.

  3. DNS Records:

    • Support for all common DNS record types, including A, AAAA, CNAME, MX, NS, PTR, SOA, SRV, and TXT.
    • Manage records through the Azure portal, Azure CLI, Azure PowerShell, and REST API.

  4. Alias Records:

    • Alias records allow you to map DNS names to Azure resources like Azure Traffic Manager, public IP addresses, and Azure Content Delivery Network (CDN) endpoints.
    • Automatically update DNS records when the underlying Azure resources change.

  5. Integration with Azure Services:

    • Seamlessly integrate with other Azure services for dynamic DNS updates and automated DNS management.
    • Use Azure Private DNS for internal domain name resolution within your Azure virtual networks.

  6. Security:

    • DNS queries are secured with DNSSEC (DNS Security Extensions) to protect against spoofing and cache poisoning.
    • Role-Based Access Control (RBAC) to manage permissions and access to DNS zones and records.

  7. Scalability:

    • Azure DNS is designed to handle large-scale DNS workloads.
    • Scalable to meet the needs of high-traffic domains.

  8. Monitoring and Analytics:

    • Monitor DNS queries and traffic patterns using Azure Monitor.
    • View detailed metrics and logs for DNS performance and availability.

Best Practices

  1. Zone Management:

    • Use descriptive names for DNS zones to clearly identify their purpose.
    • Organize DNS zones to reflect the structure of your organization or application.

  2. Record Management:

    • Use alias records to simplify DNS management for Azure resources.
    • Regularly review and update DNS records to ensure accuracy.

  3. Security:

    • Implement DNSSEC to enhance the security of your DNS infrastructure.
    • Use RBAC to control access to DNS zones and records.

  4. Monitoring:

    • Enable monitoring and logging for DNS zones to detect and troubleshoot issues.
    • Set up alerts for unusual DNS activity or changes in traffic patterns.

Use Cases

  • Hosting DNS Domains: Manage DNS records for your domains within Azure.
  • Internal Domain Resolution: Use Azure Private DNS for internal name resolution within virtual networks.
  • Application Delivery: Optimize DNS routing with Azure Traffic Manager for high availability and performance.
  • Automated DNS Management: Integrate with Azure services for dynamic DNS updates and automation.

Azure DNS provides a reliable and scalable DNS service that simplifies domain management and integrates seamlessly with your Azure infrastructure.

Internal (Private) Name Resolution Scenarios and Options

  • Scenarios:

    • Name Resolution within a Virtual Network: Resolve names of resources within the same virtual network.
    • Name Resolution between Virtual Networks: Resolve names of resources across different virtual networks.
    • Name Resolution between On-Premises and Azure: Resolve names of resources between on-premises networks and Azure virtual networks.

  • Options:

    • Azure-provided DNS: Use Azure-provided DNS for name resolution within a virtual network.

      • This is the default when you create a virtual network in Azure. Anytime you create a vNet in Azure, the platform configures it to use this option and assigns a unique private DNS suffix to it in the .internal.cloudapp.net format. Azure’s DHCP will assign this DNS suffix to any resource that obtains an IP address.
      • The default Azure provided DNS Server uses a virtual IP address of 168.63.129.16. This server limits each client to 1000 queries per second. Anything above this is throttled.
      • This option can only cover scenario 1 above (Name Resolution within a Virtual Network).
      • This option does not support WINS or NetBios.
      • We cannot enable or configure logging within this option.

    • Custom DNS: Configure custom DNS servers for name resolution within a virtual network.

      • You can host your own DNS server and forward name resolution requests to it.

    • Azure Private DNS: Use Azure Private DNS for name resolution between virtual networks and on-premises networks.

      • Azure Private DNS provides a reliable, secure DNS service to manage and resolve domain names in a virtual network without the need for a custom DNS solution.
      • This service can be used to create forward and reverse DNS zones (up to a max of 1000 per subscription).
      • An Azure Private DNS Zone can contain up to 25000 record sets, and supports all common record types.
      • After you create a Private DNS zone, it must be ‘linked’ to a vNet.
      • When linking a Private DNS Zone to a vNet, you can choose to enable auto-registration of virtual machines in the vNet to the DNS zone. This will automatically register the VM’s hostname and IP address in the DNS zone.
      • A virtual network can be linked to multiple private DNS zones, but it can only be linked to one private DNS zone with auto-registration enabled.

Public Name Resolution Scenarios and Options

  • Scenarios:
    • Name Resolution for Internet Clients: Resolve names of resources for clients on the internet.
  • Options:
    • Azure DNS: Use Azure DNS for public name resolution.
      • Azure DNS is a cloud-based DNS service that hosts your DNS domains and provides name resolution for internet clients.
      • You can manage DNS records for your domains using Azure DNS and integrate it with other Azure services.