Advice on setting firewall rules to allow internet when connected to openVPN only

Hello,

Using openSUSE 12.1 x64 with KDE.

I’ve had a look, but I’m not overly sure on the procedure required to set up the firewall to only allow internet connections when connected to openVPN.

The primary reason is to stop the connection to and from the internet should the VPN drop its connection during usage. I am happy to prevent any internet access at all unless connected to the VPN, but it is quite important that while connected to the internet the connection remains encrypted via the VPN.

I am not sure however to implement this. I would appreciate advice (or settings) required in order to achieve this. I’m assuming doing it via the Firewall settings in YaST would be the best way, but having looked nothing appeared obvious, so I’ve decided to ask here rather than mess up settings with trial and error.

Thank you in advance.