MS-102 Deploy and manage a Microsoft 365 tenant Practice Question
An administrator is onboarding a new custom domain for email in a Microsoft 365 tenant. Which step should be performed first?
⚠ Common exam trap
It's easy for candidates to confuse the order of operations, thinking DNS verification (Option B) is the first step, but Microsoft 365 requires the domain to be added to the tenant first to generate the verification token.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Add the domain in the Microsoft 365 admin center
Before you can use a custom domain for email or any other service in Microsoft 365, you must first add the domain to the tenant in the Microsoft 365 admin center. This creates the domain object in Microsoft Entra ID and initiates the verification process. Only after the domain is added can you proceed to verify ownership and configure DNS records.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Add the domain in the Microsoft 365 admin center
Why this is correct
The first step in onboarding a custom email domain is to add it in the Microsoft 365 admin center (Settings > Domains > Add domain). This action registers the domain with your tenant and generates the necessary verification token, allowing you to proceed to the next step of proving ownership. This must occur before any TXT record or DNS changes can be associated with the domain.
- ✗
Verify domain ownership by adding a TXT record
Why it's wrong here
Adding a TXT record to verify domain ownership is a secondary step that occurs only after the domain has been added to the Microsoft 365 admin center. The admin center generates a unique TXT value that must be published in public DNS, and this verification value does not exist until the domain is registered with the tenant. Attempting verification first is impossible because Microsoft 365 has no domain object to verify.
- ✗
Configure DNS records for Microsoft services
Why it's wrong here
Configuring DNS records such as MX, CNAME, and TXT for Exchange Online and other Microsoft services is performed only after domain ownership has been verified. Unverified domains cannot receive email or enforce routing rules, and Microsoft 365 will not provision a domain in DNS until the TXT verification is complete. This step is essential but chronologically later, so it cannot be the first action.
- ✗
Set the domain as the primary email domain
Why it's wrong here
Setting the domain as the primary email domain is a final administrative decision made only after the domain has been verified and its required DNS records are configured. The primary domain affects the default user principal name (UPN), email address policy, and the From address for new users, so changing it prematurely could disrupt existing user provisioning and mail flow. This should be deferred until all prerequisite checks have passed.
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Entra ID Protection and Risk Policies
Key term
Microsoft Entra ID
Microsoft Entra ID is a cloud-based identity and access management service that lets employees sign in and access resources both inside and outside of your organization.
Key term
Microsoft 365 tenant
A Microsoft 365 tenant is a dedicated, isolated instance of Microsoft 365 services created for an organization when they sign up for a subscription.
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