Say, we need to expose LXC container (LXC) or Virtualbox VM (VBM) to public network with its own IP-adress (within additionaly assigned network — ADD-net) which is to be routed through main host. When in SOHO environment it is quite okay to use LXC/VBM with its bridge based networking on main host's primary network interface (say, eth0), but it fails for colo-/hosting sysetms if switch port is security locked to one only MAC-adress due to hoster's policy.
What is the proper way to accomplish it?
I managed to do this with creating artifical bridge interface (br0), which is assigned one of the ADD-net's IP, and then bridging LXC/VBM's ethernet port to br0. Inside LXC/VBM routing is set to use br0's IP as default gateway.