In Windows Server 2003, you can choose from among three models for administering remote access permissions and connection settings:
Access by user
Access by policy in a Windows 2000 mixed or Windows Server 2003 interim domain
Access by policy in a Windows 2000 native or Windows Server 2003 domain
An essential part of planning for remote access is determining which models you can use and deciding on an appropriate one. There is enough variation among the models that attempting to mix them is a recipe for confusion. No matter which model you choose, plan on thoroughly testing your chosen access policies to make sure that you’re getting the results you intend.