logon unique

[Vincent Morlot]

I'm using Linux (debian 2.1) with samba 2.05a PDC.
My clients are windows NT4 Workstation with service pack 3.
I'm using roaming profiles so a user is able to log on few workstations.
But I'm looking for the way to block a second log when a user is already
logon into the PDC.
So that mean when the user A is connected using workstation A, he must
not be able to log on the PDC using workstation B.

Please help!

Thanks

-- 
Vincent Morlot(VincentMorlot at compuserve.com)