Preventing privacy leaks when a VPN disconnects?

view full story

http://forums.fedoraforum.org – I'm connecting to a VPN using the network manager. Sometimes the VPN disconnects and I am then connected using my own IP. I would like to avoid this situation, because it means other people can observe me on the interent. How I make it so that when the VPN disconnects that I am no longer connected to the internet? Or maybe some other appropriate solution? There are some guides out for how to do this on a Debian machine, but I couldn't find one for Fedora. Debian versus Fedora does matter in this case. Thanks for any help. (HowTos)