I'm using Mac OS and connect to a VPN to hide my location and IP (I have the 'send all traffic over VPN connection' box checked in teh Network system pref), I wish to remain anonymous and do not wish to reveal my actual IP, hence the VPN. I have a prefpan called pearportVPN that automatically connects me to my VPN when I get online. The problem is, when I connect to the internet using Airport (or other means) I have a few seconds of unsecured internet connection before my Mac logs onto my VPN. Therefore its only a matter of time before I inadvertently expose my real IP address in the few seconds it takes between when I connect to the internet and when I log onto my VPN.

Is there any way I can block any traffic to and from my Mac that does not go through my VPN, so that nothing can connect unless I'm logged onto my VPN? I suspect I would need to find a third party app that would block all traffic except through the Server Address, perhaps Intego Virus Barrier X6 or little snitch, but I'm afraid I'm not sure which is right or how to configure them.

Any help would be much appreciated. Thanks!