The Windows .NET version of Active Directory allows administrators to change domain names and, thus, reconstruct the forest. This procedure is not intended to be a routine operation and is only possible when the forest functional level has been raised to Windows .NET. The rename procedure is not simple and includes a step-by-step process that requires use of the RenDom.exe utility (see the link in Appendix A) and depends on the kind of rename operation.
The simplest case is when you rename a domain and do not change the forest parent-child structure. A more complex case is when you change the domain position in a forest tree, e.g., make a child domain a tree root domain or change the parent for a child domain. The rename procedure may require many supplementary operations, such as pre-creating additional inter-domain trusts, preparing DNS zones, configuring member computers, and so on.
The rename procedure allows you to:
Change the DNS or/and NetBIOS names of any domain without affecting the forest structure. This includes renaming a root domain, which results in changing names of all child domains.
Change the parent domain for a child domain (the new parent can be in the same or another domain tree).
Rename a child domain to be a new tree-root domain.
None of the listed operations is possible in a Windows 2000 forest.
The following rename operations are not possible:
You cannot redefine the forest root domain (i.e., the forest root will always be the same domain). However, you can change its DNS or/and NetBIOS name.
One cannot delete or add a domain: the total number of domains in a forest must remain the same. A usual promotion/demotion procedure should be used in such cases.
You cannot rename two domains in a single operation and give a domain the name of another domain. The rename procedure requires quite a long, detailed description — and so, it is inappropriate to include one here. You can find two comprehensive operation guides (about 90 pages in total) on the Microsoft website (see the link in Appendix A) if you are interested in learning more about this topic.