We need to allow Win 98, ME, 2K, and XP clients to connect to a Linux
7 server running Samba 2.2.5 in a closed networking environment. To
prevent undesired access to the server, the client user must not be
aware of the connection method. Permanent mapping is out. The client
applications need to connect, do their business(read, write on file
system), and disconnect in such a way that the user can't repeat it

I've been successful with user-level security, accessing a share set
up for a common user with all but Win 98. My method is:
"net use \\server\share aPassword /user:commonUser"
[do some file stuff]
"net use \\server\share /delete"

Win 98's version of "net use" doesn't provide for accessing the share
as another user and instead transmits the username of the logged-in
user. This presents two problems:
1. It's possible in some installations to have 1000+ clients, and the
frequency of change in the client list makes it unreasonable to keep
adding and removing users.
2. Win 98 seems to keep the "validation token" persistant, so once the
client application has logged in, the "secure" share is accessible
even after the share is deleted.

Is this a real limitation for Win 98, or am I missing something? Any
suggestions for a way to meet the security requirement and still allow
direct access to the file system?