The NordVPN app for Linux protects your sensitive data with
military-grade encryption, so that whatever you do online stays secure
and private.
More than 5000 servers worldwide. No logs of your online activity.
Secure up to 6 devices with a single account.
Access online content securely, with no restrictions.

The following can be used to start/stop NordVPN automatically:
/etc/rc.d/rc.local
  if [ -x /etc/rc.d/rc.nordvpn ]; then
    /etc/rc.d/rc.nordvpn start
  fi

/etc/rc.d/rc.local_shutdown
  if [ -x /etc/rc.d/rc.nordvpn ]; then
    /etc/rc.d/rc.nordvpn stop
  fi

NOTE: NordVPN has implemented NordLynx (WireGuard protocol) into the
app.  It is still under heavy development. However if you want to try
it, you need to install these 2 optional dependencies:

wireguard-linux-compat
wireguard-tools

Then you can switch to NordLynx with the following command:
'nordvpn set technology NordLynx'

And connect using:
'nordvpn c'

You can always switch back to OpenVPN using this command:
'nordvpn set technology OpenVPN'