Configure User Identities for New Domain Name
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1h 44m

Microsoft 365 represents a combination of Office 365, Windows 10 and Enterprise Mobility offerings – providing the most complete set of SaaS technologies that Microsoft has to offer. With Microsoft 365, organizations can deploy a complete solution encompassing both devices and applications, along with applying security and compliance policies to protect the entire suite.

This course will help you as you plan your deployment of Microsoft 365, along with configuring and managing your tenant once it’s deployed. It also covers setting up and managing a Microsoft 365 subscription for an enterprise – including managing identities, security, compliance and the supporting technologies in the Microsoft 365 stack.

This course focuses mainly on setting up and managing a Microsoft 365 tenant – including the process for setting up a trial tenant, adding your own domains, and converting your tenant beyond the trial to a fully functional production environment. Now, these steps can seem to be very easy – just click a few options, answer a few questions, and you’re done. In fact, it is that easy! However, if you’re not aware of the big picture and asking some important questions along the way, you can end up painting yourself into a corner and causing problems down the road. At best, you might need to redo some things, at worst, you leave yourself with problems on your hands that might be difficult to sort out later.

After you’re set up, we’ll move on to talking about some of the things you need to consider in your day to day monitoring and management of your Microsoft 365 Tenant and the services that make it up. We’re also going to run through a few demos – showing you some of the practical steps involved, along with some tips and tricks we’ve picked up along the way.

Learning Objectives

  • Set up a new Microsoft 365 tenant and subscription
  • Add domains to the tenant and configure them for the various service offerings
  • Perform the day to day management of your users, including managing user accounts and license assignment
  • Know how to monitor the various services in your M365 tenant and have a plan in place to respond to service alerts and manage service requests

Intended Audience

This course is intended for people who:

  • Want to become a Microsoft 365 administrator
  • Are preparing to take the Microsoft’s MS-100 exam


To get the most from this course, you should have a general understanding of networking & server administration as well as IT fundamentals such as DNS, Active Directory and PowerShell.


Once you've added your new domain into Office 365, your next step is to assign this new domain to some or all of your user accounts. Go back to the admin portal and find the users that you want to assign this license to. Note that when you are selecting multiple users like this in the portal, you can only edit their log-on domain. You can't use this option to add your new domain as email aliases for your users. In this case, we're going to add the new domain as their primary or log-on domain. So select the users that you want to edit and click Edit domains. You'll see that our new domain is available as an option you can pick from the dropdown list. If you haven't finished verifying your domain in Office 365, it won't be available to be assigned to your users until you completed that certification step. 

Note that when you change the domain for these users, they can be currently set to a different domain, or the built-in domain. All the users will have their log-on names and email addresses in Exchange Online updated to match your new domain name. Also note that this is a user impacting change, and Office 365 warns you of all the places that this will change things for your user. Their username for logging in to Office 365 will be updated. Their primary email address in Exchange Online will be updated. And any Skype meetings they've set up with the old username will need to be updated. Also, the user will have to log out of Outlook and the Office apps and log back in using their new username. Click Save and then Close to complete the process of updating your users' log-on names. You can see from the portal that the usernames have updated. Everybody's now And these changes will propagate throughout the Office 365 environment over the next few minutes.

About the Author

Jeremy Dahl is a Senior Technology Consultant who has spent the last 8 years focusing on Microsoft 365 technologies and has been an Office 365 MVP for the last 6 years. Jeremy is a self-proclaimed cloud addict who architects technology solutions that combine cloud technologies with on-premises solutions, allowing organizations to make the most of their existing infrastructure while still taking full advantage of the agility and scalability of what the cloud has to offer.

Jeremy can be found blogging about Microsoft 365 technologies on his website,, and evangelizing the Microsoft cloud on Twitter.