raising forest level from 2000 to 2003, any forseen issues?

Question

We are out to migrate from a Windows 2003 domain server including Exchange 2003 to a Windows 2012R2 server with a 2013 Exchange.

Our Windows 2003 domain has about twenty client machines one XP Pro, a few vista Pro, and mostly Windows 7 Pro. In migration experiment mode, I sought to add a Windows 2012R2 Server to the 2003 domain and got a "There are currently no logon servers to service the logon request" and a system log error of #5719 when trying to logon with 2012 to the 2000/2003 domain.

It took some searching but I found that our 2003 Server has it's Forest Funtional Level set with Windows 2000 level and Windows 2012 requires a Windows 2003 Forest level to be able to logon.

So my question is what problems will occur when I raise the Forest Level to 2003 from 2000?

You have to get rid of any NT 4.0 or Windows 2000 servers. That's the big one, I think. — Michael Hampton, Oct 16 '15 at 22:06
From what I read I shouldn't have any problem raising the forest level. But if I should will I be able to switch it back the same way? — Ron Whites, Oct 26 '15 at 14:38

score 0 · Answer 1 · answered Oct 16 '15 at 22:29

You're unlikely to have any problems at all.

A few concepts change over the years - one of the most visible ones is that there are now PDC emulators and FSMO roles, and no more PDCs. The schema changes slightly. There are now RID masters.

You should probably read the documentation Microsoft made for just this thing: https://technet.microsoft.com/en-us/library/cc781198(v=ws.10).aspx

The process is roughly to upgrade (or remove) all your pre-2003 domain controllers, and then just raise the functional level. Everything else is just best practice (and you should do it, but you should also run supported operating systems).

If you do nothing else, remember that if you have GPOs, you need to do this:

GrantPermissionOnAllGPOs.wsf “Enterprise Domain Controllers” /permission:read /domain:DNSDomainName /Replace

Or the equivalent, or your GPOs may not work.

I believe the only computers that can't authenticate to a Windows 2003 functional level domain are Windows NT 4.0, so you shouldn't have too much trouble. However, your DCs must all be running at least Server 2003.

I usually prefer to run one client OS version and especially one server OS version at a time, especially on my domain controllers, when I can.

score -1 · Answer 2 · answered Oct 17 '15 at 06:47

Raising forest function level means you are making compatibility to the level or higher you have raised. In case if you raise to 2008 you cannot have 2003 DC. In cased if you raise to 2003 you can have both 2003 and 2008 DC.

If you have planned to migrate to newer version , do proper function raise

raising forest level from 2000 to 2003, any forseen issues?

2 Answers2