Somehow interface ether2 has disappeared from my interface list. The lights still flicker so its active, But where can I add it back into the interface list?

It seems to be you renamed it.
To check default names run next command in Terminal: and find interface with default name ether2.

That is solved thank you. Now ether0 is gone. there are 6 ports. ether0 to ether5.

Is it real routerboard, x86 PC or virtualized?

it is x86