This question is Not about how to set up VPN on an Ubuntu server.
Edited: I think what I'm looking for is the way to set up a PPTP VPN client on my Ubuntu server by command line.
I have an Ubuntu server running and connected to the internet. I also have a VPN service (PPTP) running on another Linux machine. Now all I want to do is configure this Ubuntu server so that all the internet traffic it generates goes through the VPN.
How can I achieve this?