this seems to be a decent answer written up ready to go. https://serverfault.com/questions/462178/duplicate-mac-address-on-the-same-lan-possible https://server

this seems to be a decent answer written up ready to go. https://serverfault.com/questions/462178/duplicate-mac-address-on-the-same-lan-possible https://serverfault.com/questions/462178/duplicate-mac-addre... what happens depends on your LAN setup, but generally its a fail.