Allow Non Admins to log onto DC's

To configure non-admin RDP access to DCs follow these steps:

1.  Create a security group (Non_Admin_RDP_DC) for the non-admin RDP users.
2.  Add the "Non_Admin_RDP_DC" group to the  "Built-in\Remote Desktop Users" group.
3.  From the "Default Domain Controller" Group Policy, add the "Remote Desktop" security group to the "Allow Log On Through Terminal Services" key.