dit document beschrijft de werking van preferred domain controller
inhoud
It's just a preferred setting and will not prevent Lansweeper from contacting other DC's is the preferred ones are not available.
the Lastlogon attribute for user scanning specifically, it will contact all DCs in any case, since Lansweeper needs to find the highest value (most recent logon)
set the DCs that are nearest to the assets that you are scanning to speed up the queries.