In case of troubleshooting or temporary issue, you may want to be sure that a given member server always authenticate against one specific domain controller.
For this, you may want to combine two tools:
- The “time-to-live” (TTL) value for the validity of the discovered domain controller
- The ability to specifically target a given domain controller when checking the secure chanel
The first point is addressed by using the ForceRediscoveryInterval registry key introduced in Windows 2008 (and back ported to Windows 2003 in a hotfix should legacy servers live after july 2015 at your premises). It is documented in detail in the incorrectly titled article KB 939252: The domain controller locator cannot find an appropriate domain controller on a computer that is running Windows XP or Windows Server 2003.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netlogon\Parameters\ForceRediscoveryInterval DWORD value should be set to
0xffffffff for (almost) eternity to happen.
The second part is achieved using the regular
nltest /server:The_DC_I_Want /sc_query:MyDomain
Please note that this trick doesn’t allow you to make this setting persist across reboots.