Follow this recipe to find out which domain controllers run FSMO roles.
To query FSMO roles, you'll need to be signed in with an account that is a member of the Enterprise Admins group.
To locate the domain controllers running the FSMO roles, run the following command on any domain-joined device, member server, or domain controller:
netdom.exe query fsmo
Or, use the following PowerShell commands on a domain-joined system that has the Active Directory Module for Windows PowerShell installed: