Forum Discussion
Exchange Hybrid Deployment single forest multiple email domains
Hi all,
I have a question. I have 22 email domains on prems. ( Three EXC 2016). Points to a third-party mail scan.
One primary domain and two upn Sufix added to local AD. My all users are synchronized to office 365 based on UPN. The upn Sufix based users mailboxes are online. While primary domain based mailboxes are onpremises with 17 email domains being the alias and email addresses.
I enabled the hybrid component in sync server.
Now when I add my email domains in office 365 and verify them, they become Authoritative and break the mailflow. I need to run hcw so I'm also verifying my email domains. Should I verify them and set them internal relay before running hcw or is there anything else I am missing?
Thanks
Far.
I have a question. I have 22 email domains on prems. ( Three EXC 2016). Points to a third-party mail scan.
One primary domain and two upn Sufix added to local AD. My all users are synchronized to office 365 based on UPN. The upn Sufix based users mailboxes are online. While primary domain based mailboxes are onpremises with 17 email domains being the alias and email addresses.
I enabled the hybrid component in sync server.
Now when I add my email domains in office 365 and verify them, they become Authoritative and break the mailflow. I need to run hcw so I'm also verifying my email domains. Should I verify them and set them internal relay before running hcw or is there anything else I am missing?
Thanks
Far.
35 Replies
- Peter, I got a question. Upon Checking Dls and Resource (Room) Mailboxes I found they are synching to cloud with onmicrosoft.com domain suffix because they use email address domain instead of UPN domain. How will I migrate them? Can I simply migrate them to roommb1@doman.onmicrosoft.com domain? or this will through any error?
Hi Abdul. In a hybrid configuration, it is best practice to have your on-premises UPN's set to match the SMTP addresses. If the UPN is set to a domain.local suffix, then you will see these accounts syncing up to O365 with the roommb1@domain.onmicrosoft.com as you are seeing now. I would strongly advise changing the on-prem UPN's to be the correct domain suffix.
You don't have to migrate DL's. These will be taken care of with your hybrid coexistence setup when you get to this.
Speaking of the Hybrid, it is worth pointing out that once you run your HCW, it will modify your email address policy to include an alias of username@domain.mail.onmicrosoft.com for each user who is targeted by and email address policy. This alias is important, and any accounts excluded from email address policies will need to have this added manually before they can successfully be migrated,
Once you have completed your mailbox migrations to O365, it is recommended to retain an Exchange Management server to manage any attributes which still have their SOA on-premises, and also to act as SMTP relay for software and devices.
So you already have some live email accounts in O365, but you have not yet configured Exchange Hybrid? Is that correct? How are the O365 mail accounts setup for identity - are the cloud only?
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?
