source: branches/samba-3.5.x/docs-xml/smbdotconf/security/forcesecuritymode.xml

<samba:parameter name="force security mode"
                 context="S"
                                 type="string"
                 xmlns:samba="http://www.samba.org/samba/DTD/samba-doc">
<description>
    <para>
        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.
        </para>
                
    <para>
        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.  Make sure not to mix up this parameter with <smbconfoption
        name="security mask"/>, which works similar like this one but uses logical AND instead of OR. 
        </para>

        <para>
        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.
        </para>

    <para>
        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.
        </para>
                
    <para><emphasis>
        Note</emphasis> that users who can access the Samba server through other means can easily bypass this
        restriction, so it is primarily useful for standalone &quot;appliance&quot; systems. Administrators of most
        normal systems will probably want to leave this set to 0000.
        </para>

</description>

<value type="default">0</value>
<value type="example">700</value>

<related>force directory security mode</related>
<related>directory security mask</related>
<related>security mask</related>
</samba:parameter>