Forum Discussion
Exchange Hybrid Deployment single forest multiple email domains
PeterRising Out of 19 domains two are cloud only, so there users are syncing from local AD (UPN Suffix) but their mailboxes were provisioned in cloud.
Other all domains are just email domains added to Exchange on-premise online ( all user with these domains are syncing to cloud with UPN suffix which is common across.
These users have SMTP in local AD but not all proxy addresses which are there in exchange servers.
OK, and in what way does this break mail flow for you please? Can you give me an example?
Peter, Thank you.
When I add any email domain in office 365 and verify this.> Obviously the domain will become Authoritative but it should not break mail flow to on-premise exchange , but it does.
after verifying all these email domains I will be running Azure AD Connect to Sync and convert them manged.
Abdul Farooque as long as all mail-enabled objects are synchronized to Azure, there should no problem with an authoritative domain. If the domain is set to authoritative, DBE (Directory Based Edge) blocking becomes active which means if a mail will be send to a non-existing recipient in EXO, it will be blocked.
During coexistence and your migration phase, change the domains to internal relay and then analyse the mail flow bevor changing it back to authoritative (and maybe consider switch the MX record to EOP as well).
Ah I understand now. Yes this would be expected behaviour. What you would need to do is as you suggest and change the added domains to be internal relay, and then you will need to set up a send connector in Exchange Online from Office 365 to Your Organizations Email Server, and set it to deliver mail to the smart host address of your on-premises Exchange Server. This should do the trick for you.
Got it, and after this I can run hcw, right?
another concern I have many users doesn't have their Proxy addresses populated in AD, though exchange does have these proxy address. I am thing I should populate them before running sync or it will break the incoming to these aliases once the migration is completed?
