Usage: Dfsutil /Server: /PreferLogonDc: /Set This can be used to set the PreferLogonDc registry value in a Domain Controller ...

Usage: Dfsutil /Server: /PreferLogonDc: /Set  This can be used to set the PreferLogonDc registry value in a Domain Controller running OS Windows Server 2003 or above to the value provided. The valid values can be 1 or 0  This could be used to display the value in a DC as well  dfsutil /Server: /PreferLogonDc /Display