[Samba] Samba Security

[ashok cvs]

Dear all

I have a samba 3.0.21 with openldap as a primary domain controller, and all
my windows clients are
joined to my domain. i have  file servers (Domain Member servers - linux
systems) which are given access for file sharing to my clients.
so all the windows clients in my domain access the file server according to
their user permissions.
i also have some windows clients which are not joined to my domain, but are
in the same network as my PDC.
they are also able to access the file server, but it prompts for username
and password, and user gives the username and password
and access it.
is there any way that the windows clients which are joined in my domain only
should be able to access the  file servers
and the sysetms which are not joined should not be able to access file
services.

i don't want to implement ip  level security on shares, as user can change
the ip and access it.
i would like to know if file servers which are in joined to my PDC can be
given access to
only  windows clients which are joined to my domain, any other windows
client
which is not in OU=Computers ie which is not yet joined to my PDC should be
denied.

Is it possible ?
please guide me


Regards
Niranjan