I have set up an OpenVPN connection via the network manager on Ubuntu 12.04 following these instructions:
Initially I could not access any websites when connecting to the VPN network.
I then ticked the box for 'Use this connection only for resources on its network' under IPv4 Settings, Routes.
After ticking the box everything seemed to work. I could connect to the VPN network and open websites.
I only coincidentally noticed though, that although the network manager tells me that I have successfully connected to the VPN network, my IP address does not change.
I then looked into the Private Internet Access configuration files downloaded from the link above and found the port number 1194, which I opened using the firewall configuration tool Firewall.
I also unticked the box 'Use this connection only for resources on its network' and connected to the VPN network. I can do Google searches and access one or two random websites, but then I get a 'connection failed' from the browser.
It seems to connect to the VPN network successfully though. The IP address changes according to the host I am using.
I would be really great full for some tips. I tried to fix this problem for some time but have not been successful in my attempt.