Determining your business or organization's domain name takes careful planning. You domain name will become the root domain for your Active Directory tree, and all other names within the Active Directory will branch from this tree. You also have to consider the implications of your domain name and Internet communications. To use your domain name on the Internet, you have to register your domain name so that it is unique. If you have an Internet presence, you can use the same domain name because it is already registered, but you may want to consider some options to separate the two for security purposes.