Sorry for your head š
Yes Iām able to connect to the server by āBUILTIN\Administratorsā but I remove it for security reason.
I can also connect to a DB of the SQL Server if I set some right to a Domain User like āDomain\Richardā. All the permission is set in the sysmembers table. But It only works for a signle user, or a Local Group and not with Domain Group.
To give you more details about my test: I try is to connect with SQL Query Analyser with a normal Domain user to a DB of one of my SQL Server (connected on the same domain). Heās not at all an admin of anything. If I set the access with Domain\Name, it works but not with Domain Group.