I have a server connected to two network interfaces (via two different Internet services providers). The server runs Ubuntu OS. I want to use exactly one of the interfaces only for a virtualbox machine that runs on the server (dedicated interface to the virtualbox).
I want that all the incoming traffic to the server via that interface will be redirected to the virtualbox machine, and that any outgoing traffic will go through this interface.
I know that for the the first task, I need to do port-forwarding. However, I could not find a way to define rules that include all the ports.
I spent more than one day in searching for a solution, but without any success. Detailed answers or references to informative resources (examples are preferred) will be appreciated.
If you have partial answer, e.g., only about outgoing traffic, do not hesitate to send it!
Thanks in advance!