Exchange server upgrade – pt 2

This weekend was meant to be the second stage in a NT4 and Exchange 5.5 migration to Windows 2003, Exchange 2007. This process has been a big nightmare so far – this weekend wasn’t helped by the cd being unreadable by any of the machines (although you could see *some* files the setup program wouldn’t completely launch.)
Trying to think of an alternative solution I wondered if the trial version of Exchange that is downloadable from Microsoft would work. However, although Microsoft say you can actually use a purchased key on the trial version, the only trial version available is 32bit and the only supported version of exchange is 64bit. The other problem is that the 64bit version is a 5.5GB DVD so not something you can easily download on a T1 connection 🙂
Eventually we managed to get a copy of the DVD from another branch of the company and I started the install process. Unfortunately it was then that I discovered that you can only install Exchange 2007 into a Native mode AD. Initially I thought it just had to be higher than 2000. Unfortunately as I’m doing an upgrade from Windows NT domain to Active Directory I still had NT4 domain controllers from the original installation and these are not machines that the client is willing to remove. So I’m now stuck with a half finished migration.
Currently my two solutions are to split the nt4 domain controllers into their own separate LAN and then remove the records for the W2k3 servers and delete the NT4 servers from the AD LAn – this should work as the 2 domain controllers are just serving as standalone machines now so don’t really need clients to connect to them but their services are needed.
The other solution (which might be more graceful) is to use upromote to demote the nt4 servers to member servers only. At $99 per server this will be more cost efficient and graceful than splitting the network into 2 lans.

I must say that this whole 5.5 to Exchange 2007 is not an easy migration by any stretch of the imagination and I would certainly not recommend that you try and do it over two consecutive windows – especially if your original NT servers provide extra services to your existing network.