Exchange upgrade and Active Directory

We are looking to upgrade our Exchange Server from 5.5 to 2000. At this stage we are still an NT 4.0 network and not quite ready to migrate the entire network across to Windows 2000 with Active Directory.

From what I understand we can set up a limited deployment of Active Directory so that the 5.5 box can be upgraded 2000. But I’m wondering if it might be better to set up a separate Windows 2000 domain as part of our Exchange upgrade. I’m sure it’s possible to set up trust between the twodomains and might even facilitate our eventual migration to a full Windows 2000 network.

Any ideas? I’m sure some of you have had a similar decision to make recently ;p