https://github.com/hwdsl2/setup-ipsec-vpn/blob/master/docs/clients.md#linux
https://www.tecmint.com/setup-l2tp-ipsec-vpn-client-in-linux/
https://www.cactusvpn.com/tutorials/how-to-set-up-l2tpipsec-vpn-on-ubuntu/
https://www.vpnusers.com/viewtopic.php?t=2861
https://abakdash.com/2022/01/04/how-to-install-vpngate-on-ubuntu-21-10-kali-linux-and-windows-10/