I want to set up a Windows virtual machine where the only network access allowed is via a VPN connection. If the VPN connection fails, the VM should never be allowed access through my normal (ISP) connection. I've heard of software such as VPNLifeguard which checks periodically for the VPN being down, but this doesn't strike me as an elegant or secure solution.
I've read elsewhere that you can configure firewalls to block all traffic that's not going through your VPN's IP address, but what if your VPN IP is dynamic, or you can select multiple VPN servers to switch between? Then you'd have to change the firewall rules every time. Ditto for solutions which involve editing the routing tables.
Is there a solution which can take into account a VPN connection with a dynamic IP?
Since this is on a VM I can use either Windows XP or 7, and can get whatever firewall you recommend.