This parameter controls what UNIX permission bits can be modified when a Windows NT client is manipulating the UNIX permission on a file using the native NT security dialog box. This parameter is applied as a mask (OR'ed with) to the changed permission bits, thus forcing any bits in this mask that the user may have modified to be on. Essentially, one bits in this mask may be treated as a set of bits that, when modifying security on a file, the user has always set to be 'on'. If not set explicitly this parameter is set to 0, and allows a user to modify all the user/group/world permissions on a file, with no restrictions. Note that users who can access the Samba server through other means can easily bypass this restriction, so it is primarily useful for standalone "appliance" systems. Administrators of most normal systems will probably want to leave this set to 0000. 0 700 force directory security mode directory security mask security mask