Adding a New Domain as a Secondary Email Address
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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.


Sometimes when you're adding a new domain, you're not going to use it as your primary logon account. 

In this case, all you want to do with it is add new email addresses to some of our users so that they can receive email on that domain. There are two ways you can add email aliases for your users from the portal, you can add the new email addresses either from Office 365 admin center, or from the Exchange admin center. Let's look at both options. 

In the Office 365 admin portal, find the user you want to update and select them, remember that you can't select multiple users and edit their secondary email aliases, you can only edit multiple users if you're changing their logon or primary domain in Office 365. Once your user is selected, choose the option to edit their aliases, and now we're gonna go ahead and add an alias for this user. We're gonna follow our same naming format, this is gonna be, and then we'll save our changes, and then we can back out of here. Now we can see that is still her logon, but her email alias is This isn't a typical scenario, you probably are not gonna have many users that are still using the onmicrosoft domain name to log in, more than likely they'll have their primary domain as their login, and they might have a secondary domain, but this shows you how to add a alias to that user account. 

You can do the same thing by coming over to the Exchange admin center, selecting our recipients, and then mailboxes, and then we'll select Jane Cool from the list, go down to her email address, and we're gonna add an additional email address, and this'll be We're not gonna make this the primary SMTP address, this is just an alias. We'll click OK, notice that it has the lowercase smtp which means it's an alias and not and uppercase SMTP like the primary. We'll click Save, and now we're done. We can even come back here and verify that these changes have take place like we expect, back to change account, and we see the two aliases that we've added are now there and ready to go.

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.