Network failure today

This AM, I found that my iMac would not connect to the internet, after working just fine last night. Further diagnostics revealed that my PC, adjacent to the iMac worked with internet access just fine, so I am sure that my DSL modem/AC1900 router is working. I am writing this post because I switched the iMac to wi-fi, which accessed the internet just fine also. I tried removing the ethernet cable and reconnecting both ends, also tried another socket in the router. I have done a SMC reset to no avail. I have not yet tried a new Cat5e cable, as I have go out to the barn room to get another.

OSX diagnostics state that 'Ethernet cable is disconnected'.

Anyone seen this happen in their own experience?

Sounds like either the cable is bad or the ethernet port is bad. My money is on the cable.

Try the cable you have connected to the PC.

I will do that and see if that's it. iMac has worked fine through last night. Early morning of 12/24, line of thunderstorms came through. We awakened to very loud 'snap' and upon looking around, I found the DSL filter exploded across room. Cable to DSL modem out too. So was DSL modem. Replaced all of this, checking wiring, seemed OK. CenturyLink tech came out following Monday and stated everything was OK. (This is BS, pure and simple, as phone grounds are notorious for being antiquated. I have repeated asked for fiber link from house to road, and get laughed out. It is possible that something in iMac's ethernet receptacle was damaged, then failed). Thanks for your input.

Indeed it is and probable. Think it is time to change your ISP if you are not contracted.

Iatros55 said:

I will do that and see if that's it. iMac has worked fine through last night. Early morning of 12/24, line of thunderstorms came through............ It is possible that something in iMac's ethernet receptacle was damaged, then failed). Thanks for your input.

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Cannot answer your question, but is your equipment on an UPS (Uninterruptible Power Supply)? If not, probably a consideration - I've used those made by APC for decades - live in Piedmont, North Carolina and we often get thunderstorms w/ intermittent power outages - if prolonged allows me to shut down my computer(s) safely. Dave

I should explain that I live in a rural area, with only one electrical coop and only one telco that offers only bottom of the line DSL. Choice is not a choice out here. Like the Army, i have to work with what I've got.

FWIW, everything I have is on a UPS, and the house power is well-grounded (I checked). Finally put DirecTV on UPS (oh no, they disapproved for no obvious reason). Now I am left with grounding the telco lines (spark gap is so, so antiquated). I have placed another copper coated 8' ground rod, connected with 4g copper bare wire, but it did not help. I am pondering what to do next.

The ARRL Handbook recommends a special ground in certain circumstances that consists of 20' of rebar encased in concrete. I may be forced to do that, and place gas tube surge arrestors in each of the phone lines.

Any one else had this problem?

It sounds like you had a close lightning strike which took out the equipment and may have also damaged your iMac through the ethernet connector. We get thunderstorms here in our area of Texas that sound like WWIII has started. Some years back we had a close strike that took out the modems, all our TV sets, and my central air unit motor. Big $$ damage.

About the only thing you can do to protect against a strike or close strike is a total home ground system. I'm also on a electric co-op here and they'll install a system like that for you but it will cost. When we get thunderstorms around here, I just disconnect everything electronic from the power mains.