I'm using a VPN when I'm online at an unencrypted wifi. Unfortunately, at my university the connection is quite unstable and at every reconnect the VPN connection is terminated and I manually need to reconnect to it using the NetworkManager, which obviously only works if I notice the reconnect. I enabled the option to automatically connect to the VPN in the NM options, but it seems to have no effect.

Is there a way to enforce an active VPN connection before any other application can access the network connection so I can be sure not to send private data over unencrypted connections?

Cheers, Pascal