@vinylvalet 

Interestingly, the search results are all different now under that key phrase.

You can still search “Ethernet galvanic isolator” and get good results but “LAN galvanic Isolator”’ gets you to iFi products.  Their marketing guy is clearly savvy and reads internet boards.

Try “Tupavco Ethernet Surge Protector”.  It’s $31 and much nicer with an external ground wire and stronger protection.

The $13 kind are still all over the internet, but they’re at medical supply or Walmart or the like.  

Or thr back floorboard of my wife’s Land Rover.  I think she had about 50 laying there.  Each patient gets 3-4.

Yep, at Walmart:

2X RJ45 Plug Ethernet Network Surge Protector Arrester 100MHz

Two for $14.

Get now before the search terms are tinkered with!

Thanks, Dave.

I would avoid any Ethernet device with a ground wire. Based on an article I read a year or two ago, Ethernet surge protectors encourage high currents through the Ethernet cables. The better strategy indoors is to use Ethernet isolators which typically offer around 4kV of isolation between one side and another. This will force a surge current to take another path besides through the wires.

About the only place I might consider one is at the entrance to a home.  Personally I use an external gas discharge to protect the cable company's coaxial and internally use an Ethernet to fiber converter to create an air gap between their modem and my router.

@boucher Sorry to hear about your very rare negative experience with the iSilencer.  I have three iSilencers in my system to brilliant effect.  Happy listening.