Hi everyone! I'm looking to migrate my on-premise Exchange 2016 server to Exchange Server SE in a hybrid setup. Currently, all my active users are on Exchange Online, but there are some technical mailboxes still on the on-premise server. The MX records point to Exchange Online, while the autodiscover is directed at the on-premise Exchange. I have a single Active Directory and Exchange organization, with user sync handled through Entra ID Connect. There's also a public DNS record that directs emails to the Exchange server via TCP/25.
I've drafted a migration plan and would love some feedback on whether my steps look correct:
1. Install the new server, configure the name and network settings, and apply updates.
2. Extend the Active Directory schema.
3. Install Exchange Server SE within the same Exchange Organization.
4. After installation, set up the accepted domains, receive connectors, and send connectors just like before.
5. Install a public SSL certificate and assign it to the basic services: SMTP (default), IIS, POP, and IMAP.
6. Configure the virtual directories similar to the existing Exchange 2016 setup and enable MRSProxy.
7. Create a dedicated mailbox database for migrating on-premise mailboxes and other system mailboxes into it.
8. Update the NAT rules to route TCP/25 to the new SE server and adjust TCP/443 NAT to direct autodiscover requests to the SE server, along with changing the internal DNS for autodiscover.
9. Run the Hybrid Configuration Wizard (HCW) on the SE server, keeping in mind if it's possible to update the whole Hybrid configuration with this new server.
10. Finally, once everything is confirmed working, what settings do I need to remove before uninstalling the old Exchange 2016 server?
Thanks in advance for your help!
2 Answers
Your migration plan generally looks solid! Just a heads up, you actually don't need to manually create a mailbox database, as this will happen automatically during the installation of Exchange SE. Also, you can skip the standalone domain preparation since the installation will handle it unless your schema master is in a different site or if you're using a split permissions model, which is rare.
Just to clarify, you can't directly upgrade from Exchange 2016 to SE. Instead, you typically have to first add an Exchange 2019 server and then upgrade that to SE. Also, make sure your Active Directory level is compatible with 2016.
From what I've experienced, migrating directly from 2016 to SE is indeed supported. I just completed this type of migration successfully.
I’d advise against doing a double-upgrade as it's not the correct approach. One direct legacy upgrade from Exchange 2016 to Exchange SE is the way to go. Check out the Exchange Deployment Assistant for a detailed guide!
Actually, it is possible to upgrade directly from Exchange 2016 to Exchange SE according to the Microsoft TechCommunity. They support a side-by-side migration, which you can read about for more details.