How to easily replace current Windows 2003 Domain Controller running Active Directory

Our business has currently 3 servers. Exchange server, Terminal server, and the main domain controller.
All running windows 2003, with a mix of Standard and Enterprise. What is the easiest method to replace the domain controller? I was thinking of just configuring the new server with a new domain name and new Active Directory structure, and then join the other two server to the new domain. Is it that easy, or am I missing something?? My goal is to do this as quick as possible, with as little downtime as possible given the fact we are running Exhange (2003).
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KCTSConnect With a Mentor Commented:
If you create a new domain you will need to start again from scratch.

The simplest way is to add an additional domain controller to the existing domain, move the server roles (DHCP, DNS etc) and the FSMO roles.

Here are some more detailed steps that I submitted in answer to a simlar question:

Install Windows 2003 on the new machine
Assign the new computer an IP address and subnet mask on the existing network.

Make sure that the preferred DNS server on new machine points to the existing DC on the Domain

Join the new machine to the existing domain as a member server

From the command line promote the new machine to a domain controller with the DCPROMO command
Select "Additional Domain Controller in an existing Domain" and specify the existing domain.

Once Active Directory is installed then to make the new machine a global catalog server, go to Administrative Tools, Active Directory Sites and Services, Expand ,Sites, Default first site and Servers. Right click on the new server and select properties and tick the "Global Catalog" checkbox. (Global catalog is essential for logon as it needs to be queried to establish Universal Group Membership)

Assuming that you were using Active Directory Integrated DNS on the original DC(the default), DNS will have replicated to the new domain controller along with Active Directory.

You then need to move the FSMO roles - see

You will need to install and configure DHCP (if used) on the new machine

Make sure all clients point to the new server tor their preferred DNS server.

You can then switch off the original DC to make sure all is ok - if so switch it back on and then DCpromo it to remove its DC status before removing it from the domain.

ryansotoConnect With a Mentor Commented:
I would not add a second domain that will only complicate things.
I would bring the new server up then run dcpromo.  Once dcpromo is done give the server a few hours depending on how much data there is in AD to replicate.  
Also this assumes you know how to configure the new server (local tcp ip properties)
Once thats done you would transfer the FMSO roles from the old server to the new one.
Once the roles are transferred shut the old server down and make sure all network services can still be accessed.
If your good for a few days (some people leave it a week) then you can run dcpromo on the old box and remove it.
shake74Author Commented:
Thanks KCTS for the detailed answer, I will give it a try here in a day or two and let you know how it goes. thanks for the quick response!!
shake74Author Commented:
Thank you both for fast responses. I awarded more points to KCTS for more detail in his explanation. Thank you both !
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