We are dealing with a badly configured VPN connection from a vendor, which set up the default gateway but doesn't route traffic anywhere beyond their VPN zone.

I managed to do some ad-hoc routing to configure a computer in a way that it can reach the vendor's VPN, our local network as well as the internet. I then tried to turn this into a script, but that failed since the interface number of the VPN changes on every connection.

Is there a way in Windows XP and/or Windows 7 to configure custom routing on the client side of a VPN connection? What I would like to do is to have a script running just after the connection comes up that changes the routing table (similar to an ifup script on UNIX).