Outdoor Ethernet Run

The cable in the ground is less likely to be the problem than the terminations at the end.

What kind of cable is it? Do you have a link to the actual reel that you bought?

Have you the cable terminated into a wall box on each end or did you just put plugs straight onto the cable itself.

The solid cores shouldn't be moved too much once installed as they can break and it is far more reliable to run them to a box and take a flexible patch cable from there.

So what happened to previous cables OP? I've had standard ethernet cat 5 cable buried outside for years with no problems.

How have you joined it in the garage?

Thanks for the feedback - needs a bit more specific detail to be sure of what you're saying.

You say you used the tool and the sequence was correct, but it would help to be more complete in your description.

You can probably solve this with what you have.

Does that mean you used the cable tested on the cable from the house to the garage and it checked correctly.

Does it mean that you also checked the cable running from the garage to the shed and that checked out too?

There are a hundred different things that could be classed as joiners. Very few are worthwhile.

If you got one in a hardware shop that is light brown plastic like a phone extender it'll rarely work.

Spare AP? What model? If it has multiple sockets did any lights come on?

By not work do you mean it didn't give you an internet connection, but perhaps the computer or the router in the cabin detected a "link" up.

I'd also replace your joiner with a simple 20 quid switch, but you're not going to get that or a 100' cable delivered before this afternoon!

Can you post a picture or two of the parts around where you join it?

If your cable is testing okay with a basic tester, have you tried connecting a known-good switch at both ends, just in case your access point is blown (or the network port in the main house feeding the cable)? You said you'd tried a spare access point in the garage without success. Maybe bring it back to the main house and connect it directly to the network port feeding the garden cable, and confirm that port is still okay?

My two brothers live next door to each other and have CAT5 running between the two houses and a small studio. During the storms a couple of months ago, something took out all the equipment connected to inter-building cables (four devices in total). The cables themselves were fine, three out of the four pieces of equipment looked like they were alive (power lights etc) but the Ethernet ports were dead. I replaced the failed access points & switches, and everything is fine once more, nothing wrong with the cables themselves.

(The same storm took out all the equipment feeding external PoE runs for CCTV on another friend's business.)

You can avoid this sort of thing by running fibre between the buildings and using fibre-to-copper converters at each end. This keeps each building electrically isolated from the others. It's more hassle and more expensive though.

What did you do the last three times this failed on you?

You quite right, but OP wasn't specific, first stating "no internet", then vaguely saying no connection(which could mean either) and ignored @niallb questions

Yeah, if link was ON all the time, this does not add up, unless some miss-config

The link LED operates at the OSI physical layer and can be present even if a cable is compromised by water as the link may establish but just not allow higher frequency transmissions at the data-link layer.

What would be telling is: what was the network speed shown as when the computer was in that error state?

The speed @10-10-20 was referring to is the negotiated link speed. If there's an established Ethernet connection, the interface will register a speed. Probably 100Mb, hopefully 1000Mbit. It's got nothing to.do with a configured data connection and should be visible on the PC if connected directly. You may be able to tell the speed from the colour of the activity LED if "lights come on" on the AP/Router

What exactly does "connection" mean here? It physically felt firm, LEDs were solid or flashing, the router detected and displayed the device at the other end, you could communicate between devices at an IP level (e.g. using ping) or something else?

Thanks, I actually deal with this kind of thing for a living ;) If the OP could identify how far up the layers it was working it would be great.

Damp would actually be a problem earlier at layer 1, the physical layer, since it would cause signal degradation. Depending on how bad it might only be detected by layer 2 mechanisms like CRC.

If damp isn't causing layer 2 to have issues then there's no mechanism for it to cause issues in layer 3, beyond some tiny improbable chance (close to 1 in a billion) that the CRC failed to detect an error in a particular packet. Typically you're sending way more than 1 packet so that's implausible as a mechanism for L2 to appear fine but to cause errors at L3.

So I'm not sure what you mean here. It's plausible that any layer might intermittently work all right. And there are ways for L3 to fail when lower layers are fine, but physical problems with the connection aren't among them.