Question: Routing ethernet outside.

[Pulsar]

Ok - I don't intend to actually do this, but something ocurred to me.

I know never to route ethernet outside. The difference in ground potentials between the locations could potentially cause issues.

Also, people comment on lightning strikes. But something occurred to me. How is it that we get warned away from ethernet outside, but if you have a cable modem then your cable modem is connected (sometimes directly) to a cable run... outside. As far as I can tell the cable coming into my house is nothing more than standard TV antennae grade coax.

Aren't the odds equal that you're gonna get your cable modem blown out by a strike or gonna get a nic hooked to an outside eithernet cable blown up by a strike?

 

[amdskip]

The cable coming in should be grounded outside with a metal stake right into the ground IIRC.

 

[cmetz]

Your telephone NID has a surge protector and lightning arrestor. I don't think your CATV demarc does, but some of them may have a ground - in any case, the network has a ground, and coax has some properties that I believe make it more resilient to these problems. Still, surges and lightning can happen and can damage equipment on those lines.

It's not that you can't safely do Ethernet outside, it's that there's a whole lot of things you have to take into account and protect against. The folks who design telco and CATV networks have a lot of engineers who spend their days thinking about these problems and have had many years to figure it out and get it right. Somebody who has no experience with this problem set who blindly runs cat5 outdoors to run Ethernet over is very likely to get themselves into trouble, hence the general advice to just not do it.