A. By default, all DCs register their service records with a priority of 0 (the highest) and a weight of 100. If you don't want a certain DC to register as many requests as others, you can lower its weight. If you don't want it to service any requests unless no other DCs are available, you can lower its priority.
To lower the priority, perform the following steps on the DC that should have a lower priority.
1. Start a registry editor (e.g., regedit.exe), and access the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netlogon\Parameters subkey.
2. From the Edit menu, select New, DWORD value. Enter a name of LdapSrvPriority, and press Enter.
3. Double-click the value, set it to decimal value (e.g., 200), and click OK.
4. Exit the registry editor.
5. Start Netlogon to register the new DNS priority (e.g., Net Stop Netlogon, Net Start Netlogon).