I have a VirtualBox VM configured to route all of its traffic through a VPN (using an OpenVPN script and iptables, but that should not be relevant for the purposes of this question).
I would like to configure a Debian VM to only connect through this VPN VM, which I intend to do using an internal network.
↑ (internal network)
I have enabled the two adapters necessary to do this for the VPN VM. One for the VPN VM to connect to the internet, and the other for the internal network.
ifconfig in the VPN VM only shows
eth0, the interface used for the internet connection adapter, and
tun0, which I assume is the VPN tunnel. Not sure if this is relevant or not.
How can I find the relevant IP addresses of the VPN VM?
Which entries do I need to add in
/etc/network/interfaces in the Debian VM so the connection works?