We currently have a single server running Windows 2003 Server R2 SP2 Standard x32 and Exchange Server 2003 SP2 which handles everything - print, file, apps, DHCP, DNS, AD, etc. It formerly ran Windows 2000 Server and had an in-place upgrade applied to W2K3. Since then it's not been 100% stable. I've persuaded the powers-that-be to purchase a new server which has Windows Server 2008 x32 pre-loaded.
I need to migrate *everything* to the new server. Once I've done this I'll be reformatting our old server, reinstalling W2K3 and Exchange 2K3, and then I want to migrate Exchange back from the 2K8 Server to the 2K3 Server and have it run solely as an email server (NB we use Outlook Web Access extensively). The 2K8 Server will continue to be the Primary Domain Controller. Fortunately we have only 2 apps that are server-based - a FileMaker Pro database (which is accessed by specifying the IP address of the server that holds the database files) and Quickbooks data files. Everything else (aside from the Exchange Server) is Office documents and similar.
What do I need to do to complete all this successfully, especially in reference to IP addresses? Our current W2K3 PDC's IP address is 10.100.200.10 (which is also the Exchange Server's IP address), and our DNS servers are 10.100.200.11 and 10.100.200.12 so in addition to migrating everything I'm wondering what needs to be done to give the new W2K8 server the old W2K3 server's IP address (obviously initially the W2k8 server will have to have a different IP address), and then what IP address should be given to the W2K3 Server once it is set up as purely an email server?