You must to create a health check entry that checks the Internet connectivity.
- In the Managment Console Configuration > Health Check > General; click New.
- Set the type of check as HTTP and add the URL used to check the Internet connectivity.
In the VPM policy, add a forwarding layer with two rules.
- The first rule forwards the traffic to an upstream proxy if the healthcheck for the user defined is sick (you define this in the service by selecting a health status object and you set the status to sick)
- The second rule sends the traffic directly to the Internet without forwarding.