Question about the 5 Domains hosted on Microsoft365

Question

My organization has 6 registered domains. One we rely on and the other 5 are ancillary and used to a lesser extent by fewer people. All of these domains are listed when I look in Microsoft365 and 4 of the 5 show their DNS coming from AWS and the last shows its DNS hosted at a third party.

Aside from the primary, none of the remaining domains are showing up with active user accounts in the Microsoft365 admin interface.

I'm moving our company to SonicWall's Web App Security for Office365 from ProofPoint. SWAS sits parallel to Microsoft365 in the cloud and filter before email arrives at our inboxes. But SWAS is designed only to work with Office365 and its applications.

Since all of these domains are listed within Microsoft365's domains area does that mean that all of that email passes through Microsoft365 when people are retrieving their mail? If so, then these 5 domains will be filtered by SWAS since they are passing through Microsoft365 en-route to the end-users mailboxes. If not, then I need to find an alternative solution to email filtering for those 5 domains.

I know its confusing. I'm still sorting this out myself but the money involved in changing things is too substantial not to ask questions.

Thanks in advance

Answer 1

Hi @Allan J. Ashinoff ，

Since all of these domains are listed within Microsoft365's domains area does that mean that all of that email passes through Microsoft365 when people are retrieving their mail?

Have you already updated these domain's MX records to point to Microsoft 365? If haven't, per my understanding emails to that domian won't pass through Microsoft 365.

Reference: Domains FAQ

---

If an Answer is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.