How to specify the output network card?

[aa51513]

Since docker is running, the docker container has created a large number of bridge network cards in the system, and some other applications have also created some tun/tap network cards.

These network cards cannot be used as Internet output.

But obviously, vpncloud cannot know this,

so I want to ask, how should I configure it so that vpncloud knows which network card should be used to punch holes?