Identify domains and custom domains

  • 2 minutes

Azure DNS enables you to host your DNS domains in Azure and access name resolution for your domains by using Microsoft Azure infrastructure. You can configure and manage your custom domains with Azure DNS in the Azure portal. By accessing your domains in Azure, you can use your same credentials, support agreements, and billing preferences as for your other Azure services.

Before you begin using Azure DNS to host DNS records for your domains, there a few important concepts to review.

Things to know about domain names in Azure

Let's examine how an initial domain name and custom domain names are implemented in Azure.

  • When you create an Azure subscription, Azure automatically creates a Microsoft Entra domain for your subscription.

    Note

    You must be a global administrator to perform domain management tasks. The global administrator is the user who created the subscription.

  • Azure applies an initial domain name to your initial domain instance.

    The initial domain name follows the form <Your Domain Name> followed by .onmicrosoft.com. For example, yourdomainname.onmicrosoft.com.

  • The purpose of a custom domain name is to provide a simplified form of your domain name to support specific users or tasks.

    Organizations commonly implement custom domain names to enable users to access their domain by using credentials they're familiar with.

    Consider the Azure Administrator Incorporated Microsoft Entra domain. Azure creates the initial domain name for the Microsoft Entra instance as azureadminincorg.onmicrosoft.com. A custom domain name for the instance could be azureadmininc.org.

    Screenshot that shows how to create a custom domain name for a Microsoft Entra instance in the Azure portal.

  • The initial domain name is intended to be used until your custom domain name is verified.

  • Before a custom domain name can be used by Microsoft Entra ID, the custom domain name must be added to your directory and verified.

  • The initial domain name can't be changed or deleted, but you can add a routable custom domain name that you control.

  • In Microsoft Entra ID, domain names must be globally unique. When one Microsoft Entra directory has verified a specific domain name, other Microsoft Entra directories can't use that same domain name.