Removing Exchange email addresses (O365 migration)

Liquidfox · 7 Dec 2018 at 15:35

Afternoon all,

I've recently moved a single domain from an Exchange server into 365, the remaining domains (and mailboxes) will be moved in phases. As part of the migration, the user's original mailbox on the Exchange server is still receiving emails from other internal users even though I've done the following:

Changed the primary email address to a dummy address
Moved the X400 address to the new mailbox (in case this is what Outlook was tracking)
Removed the accepted domain

The only solution I can think of at the minute is to create a transport rule to state that any emails sent to the old mailbox are forwarded to a mail contact which is the new 365 account. The user doesn't want to have everyone manually remove them from their Outlook MRU list, deleting the mailbox altogether isn't an option as that would result in bouncebacks.

paradigm · 7 Dec 2018 at 16:56

If what I'm reading is correct then your on-prem users no longer have "@originaldomain.tld" as a proxy address, and the exchange server isn't hosting that domain at all now?

I think you can get away with using the "targetAddress" property in AD to redirect the mail.

Caged · 8 Dec 2018 at 20:36

I assume this isn't a hybrid?

katana6434 · 11 Dec 2018 at 17:29

By domain I assume you mean SMTP domain? Without more detail, I would say the way you have done the migration, should not have been done that way. You ideally need to the Hybrid Connectvity Wizard to create a connectionm between your onprem Exchange and Office 365. This will take care if all the coectsinstence issue you seem to have.
You can do it manually, but using the HCW is a lot easier.

Liquidfox · 17 Dec 2018 at 16:57

katana6434 said:
By domain I assume you mean SMTP domain? Without more detail, I would say the way you have done the migration, should not have been done that way. You ideally need to the Hybrid Connectvity Wizard to create a connectionm between your onprem Exchange and Office 365. This will take care if all the coectsinstence issue you seem to have.
You can do it manually, but using the HCW is a lot easier.

Yep, exactly this. We switched to the Hybrid configuration immediately after this when my brain realised this wasn't feasible for everything else... Didn't realise HCW was so easy!

katana6434 · 18 Dec 2018 at 21:56

Glad you sorted it. Once you have done it once you realize how easy HCW is.