Lower Domain Functional Level
You cannot set the domain functional level to a value that is lower than the forest functional level.
Lower domain functional level. When you deploy a new forest you are prompted to set the forest functional level and then set the domain functional level. The domain functional level is programmatically raised to the second functional level by directly modifying the value of the msdsbehaviorversion attribute on the domaindns object. When attempting to downgrade lower the dfl of a domain you would first need to downgrade the ffl to the same level as the required dfl to be configured.
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 need enterprise admin rights in order to change the forest functional level. You can set the domain functional level to a value that is higher than the forest functional level but you cannot set the domain functional level to a value that is lower than the forest functional level.
I was able to. The domain functional level dfl for all the domains in a forest has to be raised first before you can raise the forest functional level ffl. In this lab i had the domain and forest functional level set to server 2016.
You can also use these commands to raise the functional level instead of using the active directory users and computers or active directory domains and trusts management consoles. Domain admin rights should be enough to change the functional level of a single domain but it looks like this is not the case when lowering it although i wasn t able to find any documentation for this. We will use set adforestmode to lower the forest functional level ffl and set addomainmode to lower the domain functional level.
This was fine until a few days later when i needed to test an application that was not supported for functional domains and forest levels greater than server 2012r2. Domain functional level dfl determines the features of a domain controller dc based on the windows server operating system os it runs on. Forest takes precedence as the minimum functional level of each domain in the forest.
While a domain admin account can successfully raise the domain functional level you must have at least enterprise administrator or equivalent permissions to lower it. The domain functional level is raised to the second functional level by using the ldp exe utility or the adsiedit msc utility. Die folgenden tabelle stellt dar wie sich die windows server versionen bezüglich domain functional levels geändert haben.