[Samba] GPOs: only Default Domain Policy is being applied, ohers are ignored -- SOLVED

[Miguel Medalha]

>> I recently discovered that only the Default Domain Policy is being applied.
>> All other GPOs seem to be ignored. All Sysvol filesystem objects have the right permissions. Both DCs are running
>> Samba 4.4.3 over CentOS 7. There are no related errors in logs or Windows Event Viewer. Other policies did work
>> before. I noticed that the corresponding filesystem objects were lastly placed on users’desktops four days go.


This problem was not Samba related, it was caused by a Microsoft security update for Group Policy applied to the Windows clients. The culprit was mainly the following:

MS16-072: Security update for Group Policy: June 14, 2016
https://support.microsoft.com/en-gb/kb/3159398


The following page explains the issues and the corrective measures. 
https://support.microsoft.com/en-gb/kb/3163622

In sum:

    Add the Authenticated Users group with Read Permissions on the Group Policy Object (GPO).
    If you are using security filtering, add the Domain Computers group with read permission.