What is the best practice to migrating Windows 2012 R2 with Exchange 2016 to Windows 2022?

Hello Ricardo luna, Thank you for posting in Q&A forum. Based on your description, I understand the current environment and the migrated environement below: Old AD: Windows Server 2012 Old Exchange: Windows 2012 R2 with Exchange 2016 New AD: server 2022 New Exchange: Windows Server 2022 with Exchange 2019 The minimum requirement to add one 2022 domain controller is a Windows Server 2008 functional level. The domain also has to use DFS-R as the engine to replicate SYSVOL. Here are my suggestions you can do: 1.Check the SYSVOL is DFSR.Check steps: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DFSR\Parameters\SysVols\Migrating Sysvols\LocalState registry subkey. If this registry subkey exists and its value is set to 3 (ELIMINATED), DFSR is being used. If the subkey does not exist, or if it has a different value, FRS is being used. If SYSVOL is DFSR, it is OK, if SYSVOL is FRS, you need to migrate to DFSR first. 2.However, you want to migrate Exchange from Exchange 2016 to Exchange 2019. The functional level must be Windows Server 2016 or Windows Server 2012 R2 So please check if the functional level is 2012 R2 or 2016. If no, you need to upgrade the functional level to Windows Server 2016 or Windows Server 2012 R2. 3.Before you upgrade the functional level to Windows Server 2016 or Windows Server 2012 R2. You must make sure the DC version is equal or higher than domain functional level, and make sure domain functional level is equal or higher than forest functional level. Forest and Domain Functional Levels https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/active-directory-functional-levels 4.Add 2022 server to domain and add DNS, AD DS and GC on this 2022 server. 5.Check this new DC health by running DCdiag /v and AD replication by running commands below: repadmin /showrepl >C:\rep1.txt repadmin /replsum >C:\rep2.txt

repadmin /showrepl * /csv >c:\repsum.csv 6.After upgrading the new DC, you can test the health of the AD environment. Make sure Group Policy, Permissions, and Replication are working properly. If everything is OK. Transfer FSMO roles to new 2022 DC. 7.Check if the old DC was a DNS server, update the DNS client configuration on all member workstations, member servers, and other DCs that might have used this DNS server for name resolution. If it is required, modify the DHCP scope to reflect the removal of the DNS server. Check if the old DC was a DNS server, update the Forwarder settings and the Delegation settings on any other DNS servers that might have pointed to the removed DC for name resolution. 8.Demote the old DC if there is no other roles on the old DC. 9.Add one 2022 server to domain, migrate Exchange from Exchange 2016 on 2012 R2 server to Exchange 2019 on new 2022 server. After migrating the mailbox, after the Exchange migration is successful, you can clean up and uninstall Exchange 2016 from the old server. Note: 1.Since your environment is a single-domain controller, it is recommended that you first back up the primary AD, then install additional 2022 AD domain controllers on the existing domain environment. You are invited to refer to the following link: https://geekershub.com/how-to-migrate-windows-server-2012-to-2022/#:~:text=How%20to%20Migrate%20Windows%20Server%202012%20to%202022,8%208.%20Change%20Schema%20Master%20role%20...%20%E6%9B%B4%E5%A4%9A%E9%A1%B9%E7%9B%AE. 2.Back up your existing Exchange 2016 environment and migrate mailboxes from Exchange 2016 to Exchange 2019 on a server running Windows 2022 as per the new Exchange 2019 server. You are invited to refer to the following link: https://techijack.com/exchange-server-2016-migration-to-exchange-2019-steps/ I hope the information above is helpful. If you have any question or concern, please feel free to let us know. Best Regards, Daisy Zhou

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