[electronbeam]

Power them from a pure sine wave inverter connected to a battery thats being charged. Aka a good UPS

[mschuster91]

That's not good enough - everything attached to the computer (including network gear, unless it's fiber) must be powered by the same UPS, or you have pathways for lightning current to enter.

[Moru]

Some UPS for consumers even have an ethernet through-port so you can connect your internet cable from the wall to the UPS before it touches your router.

[amelius]

Ethernet has galvanic isolation.