VPN File and Folder Permissions

[RDK]

I have set up a VPN server on my network using PPTP and
native XP functionality. I have tested it successfully
from an XP machine on another internet connected network
with a userid and password created only for this
purpose.

To my surprise, this id (which does not exist in any
groups or folder permission lists) seems to have full
access to shares on the VPN server PC. Is this normal?
If yes, is there a way to restrict access.

Thanks....RDK