[Samba] Disable Administrator Account

[Fink Oliver]

Hi,

I have a samba setup as a PDC.
Everything works fine - but today I logged
onto a workstation locally (not to domain) with
the user Administrator - and I saw that I have access
to all my shares and that this user is mapped to
root 

I don't use a "username map" file .....

I disabled the administrator account in smbpasswd -
but its still the same.

I also have a password set to the admin account in smbpasswd
but logon to the workstation where the password is empty!!!!


What can I do ?

How can I disable the administrator - account.

Thanks a lot 

Oliver