surge protection

This site motivated me to get a license plate cam, but I'm worried that lightning could strike the tree in my front yard and follow the LPR cam's ethernet cable inside to fry my entire network. I'm using a Ubiquiti ETH-SP-G2 ethernet surge protector, but I read that nothing can stop a direct...

As a rare thunderstorm rolls through here, I'm just wondering- how long a run of Cat5 cable do you put in before starting to think about surge protection? Or does that even do any good? For example I have about 40' running at ground level to a camera near the front fence for a license...