I have a forest in which the root domain is a 2K (only one 2K server which is the domain controler).
This domain has a child 2K domain.
Both domains are in mixed modes. The child domain DC is also an Exchange 2000 server.
I beleive that the GC is the DC of the root domain.
This is running fine.
I want to install an Exchange 2003 server in the root domain. The Exchange 2003 server will also be a 2003 DC. To do that, I need to upgrade my root domain to 2003 (by running adprep/forestprep and adprep/domainprep).
Is it possible to do ? What are the risks for the child domain?
Thanks for any piece of advice. And of course, I'm in a rush.
Yes you can do that, but be careful about moving the forest to full Windows 2003 native mode.
Risks are minimal - this is a standard upgrade path and there are plenty of resources on the MS website about upgrading a forest bit by bit from 2000 to 2003.
Also read the upgrade docs on Exchange 2000 to 2003.