internet access via vpn permanently

hi all,

i’m finding the solution to slove a problem of below, can yoi help?

I should 1 pc thru ROS pptp client to connect other VPN server.
However, the VPN connection may down or dusconnection, then the PC will dirrct access internet withou VPN.

May I know any solution can be prevent PC access internet during VPN connection is lost?
That mean,
VPN connected, then PC internet access via VPN
VPN disconnect, then PC can’t access internet

sorry for my poor english and hope one of you can be helping me.