You may have seen this Article where it shows how a flash drive shaped device can completely fry out all the components of a computer. This is very shocking(pun intended) for me as an internet cafe owner.

Article: http://techcrunch.com/2015/03/12/this-usb-drive-can-nuke-a-computer/

But whats even scarier is the thought that someone could do this same attack over the local Ethernet cables and take out all my computers including my router without looking that suspicious. My question is: Is The USB flash drive attack also possible over Ethernet and if so will it affect all my computers. Also, is there anything i can do to protect against the fake usb flash drive/ethernet attack.