In order to use VPN on Ubuntu, we need to install support for the VPN protocol:
PPTP (Microsoft VPN)
sudo apt-get install network-manager-pptpCisco VPN
sudo apt-get install network-manager-vpncOpenVPN
sudo apt-get install network-manager-openvpn
How to use:
1. Click on the network-manager in the system tray
2. Choose VPN Connections -> Configure VPN: Click Add
3. You might have to restart the network-manager (killall nm-applet; nm-applet &)
4. Now the VPN connection should be shown in the network-manager