Domain Functional Level Compare

If you have to revert to a lower functional level with a version of windows server that is earlier than windows server 2008 r2 you must rebuild the domain or forest or restore it from a backup copy.

Domain functional level compare. It also determines which windows server o s. Feature set of a particular dfl will be available for a dc if it runs on the operating system version that is compatible with the functional level. You can run on domain controllers in the domain or forest.

With windows server 2012 and r2 it is possible to roll back forest and domain functional level with limitation as defined in table in the link. Today i recognized that it is not easy to find a comprehensive summary table about active directory domain and forest functional levels operating mode on the internet. When the functional level of a forest or domain within active directory is raised certain set of advanced features become available to the users.

The forest functional level ffl determines the features of active directory domain services ad ds that are enabled in a forest. It specifies a minimum functional level at which all dcs operate. So you can proceed with raising your functional level if it is not already configured to work in 2008 r2 level.

Domain functional level dfl determines the features of a domain controller dc based on the windows server operating system os it runs on. Before raising the forest functional level to 2008 r2 you have to make sure that every single dc in your environment is at least windows server 2008 r2 and every domain the same story. Functional levels determine the available active directory domain services ad ds domain or forest capabilities.

However functional levels do not affect which operating systems you can run on workstations and member servers that are joined to the domain or forest. In your case you have only two domain controllers and both of them have 2008 r2 installed. There are some explanations with the functions up to windows server 2008 r2 and some on the differences between windows server 2008 r2 and windows server 2012.

Under the general tab the domain functional level and forest functional level is displayed on the screen. Domain functional levels and forest functional levels. They also determine which windows server operating systems you can run on domain controllers in the domain or forest.