A file in Microsoft Windows NT Service Pack 3 or later that allows administrators to increase password strength. The file establishes the following rules for password creation:
. , ; : * & % !
To install passfilt.dll, first install Windows NT Service Pack 3 or later on your domain controller, which copies passfilt.dll into the %SystemRoot%\system32 directory. Then use registry editor to edit the following key:
and create or modify the following values: