Office 365 - Hybrid migration. How to accepted domains ?

[Dev Azure]

Hi PPls.

I have hybrid setup in place and migrated 50% of users to office 365. All looks good. Now i have users from differant accepted domain(primary SMTP address set to differant domain for those users).

Question:

- How will i migrate the accepted domain email address to office 365. I understand the UPN needs to be matched for the migration.

- Will i need to add another UPN for my accepted domain in onprem AD and sync it with Azure AD and also, verify the accepted domain in office 365 domain ? then add the accepted domain in office 365 exchange.

Please clarify what is the right approach. For email flow, no centralized hub configured. 

[#2]

Hi,

You will need to do the following:

• Validate the domain on Office 365
• Add the UPN to onprem
• Add the domain to the Exchange Onprem
• Do a Delta Synchronization on AADConnect
• Run Hybrid Configuration Wizzard to accept new domain
• Verify Connectors
• Create a test user and test mail flow internally
• Change MX record to Office 365 
• Test mail flow externally
• Migrate the test user to Office 365
• Create or change the users to the new domain
• Migrate Mailboxes to Office 365

[#3]

Thanks for the reply.

Accepted domain is already added in on-prem and i have users with that SMTP primary address.

So now, i need to add the domain in azure - > add one more UPN for the domain in on-prem AD -> do a sync -> then add the domain in office 365 ?

is this correct ?

[#4]

Hi Devaraj,

Validate the domain only on Office 365 you do not need to validate on Azure.

Then add the upn and do a sync.

[#5]

Sorry, I meant,

- Verify the domain in Office 365 for Azure AD sync

 -  then,  add UPN suffice in on-prem AD for the accepted SMTP domain - do the sync

- Adding accepted domain in office 365 exchange online  will automatically happen ?

Any other consideration i need to take ?

[#6]

Hi Devaraj,

Yes, that's the process.

After you validate the domain in Office 365 domain's it will be added in Exchange Online.