FSMO roles are specific Active Directory roles that are required for the proper functioning of a domain. These roles include the Schema Master, Domain Naming Master, Primary Domain Controller (PDC) Emulator, and Infrastructure Master. Each of these roles has a specific set of responsibilities, and it is important to ensure that these roles are assigned correctly to ensure the smooth operation of the domain.
There are a number of ways to check the FSMo roles that are assigned to a domain. One way is to use the Active Directory Users and Computers snap-in. To do this, open the Active Directory Users and Computers snap-in, and then expand the domain that you want to check. Right-click on the domain name, and then select the Operations Masters tab. This tab will show you the FSMo roles that are assigned to the domain.