2003 to 2016 DFL/FFL

Question

I am in charge of 3 forests that are all configured in all joined into a forest trust. two of the domains are 2003 dfl/ffl while 1 is 2008 r2. I have exchange 2007 in place. I am looking to upgrade the DFL/FFL of the lower level domains before raising the 2008r2 domain dfl/ffl then to Windows 2016. In devising my strategy I am trying to determine if I can go straight from windows 2003 to windows 2016 DFL/FFL or must I go to 2008 r2 first. I am aware that I have to migrate FRS to DFS-R as part of this process. Also, does exchange 2007/2010 support DFL/FFL 2016?

Answer 1

Yes, basically. Above is per domain. One domain doesn't affect the other in respect to this.
https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/active-directory-functional-levels

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Answer 2

I am trying to determine if I can go straight from windows 2003 to windows 2016 DFL/FFL or must I go to 2008 r2 first.

Single step is fine

I am aware that I have to migrate FRS to DFS-R as part of this process.

While a good practice it isn't required until you want to add 2019 domain controllers.

Also, does exchange 2007/2010 support DFL/FFL 2016?

Some info here.
https://techcommunity.microsoft.com/t5/exchange-team-blog/exchange-server-2007-supportability-matrix/ba-p/598981
https://learn.microsoft.com/en-us/exchange/plan-and-deploy/supportability-matrix?view=exchserver-2019

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Answer 3

Thanks for the reply. considering I am going to windows 2019 as the OS l assume the first steps would be to introduce windows 2019 in all 3 trusted domains and do the FRS to DFRS migration before I start the DFL/FFL upgrade, right?

Answer 4

Its the other way around.

The two prerequisites to introducing the first 2019 domain controller are that domain functional level needs to be 2008 or higher and older sysvol FRS replication needs to have been migrated to DFSR
https://techcommunity.microsoft.com/t5/Storage-at-Microsoft/Streamlined-Migration-of-FRS-to-DFSR-SYSVOL/ba-p/425405

I'd use dcdiag / repadmin tools to verify health correcting all errors found before starting any operations. Then stand up the new 2019, patch it fully, license it, join existing domain, add active directory domain services, promote it also making it a GC (recommended), transfer FSMO roles over (optional), transfer pdc emulator role (optional), use dcdiag / repadmin tools to again verify health, when all is good you can decommission / demote old one.

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Answer 5

Ok, got it. So based on your input, I first need to get the 2 2003 domains up to 2008 r2 DFL/FFL to match the existing 2008 r2 domain. Migrate FRS to DFS-r THEN I can introduce Windows 2019 into all 3 domains and upgrade to 2016 FFL/DFL at my leisure?