iptables , search google for it . The idea is you only allow normal internet connection to the VPN server itself , so openvpn can create the tunnel , everything else goes through that tunnel which when openvpn is not connected will result in no internet connection . a l l n e t w o r k t r a f f i c t h r o u g h o p e n v p n u s i n g i p t a b l e s u p f i r w a l l w i t h iptablestoonlyallowvpnand many more <| sep |> Well offside , but what a ball by Blind <| sep |> It ' s a documentary about Pavlichenko , I ' m not sure about the name . <| sep |> Are you there to sell something ? Dress a little nicer . Are you just there to attend ? Dress however you want . <| sep |> I would bet less than 1 % of Mac users max out 16 GB RAM . <| sep |> rawfuleyebrows in case anyone wants to see some extreme cases