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Comment by a-dub | Hacker News Reader

i once lived in an apartment in an old building where if you turned on the light in the bathroom the dsl would lose sync.

why this would occur i'll never know. (probably old telephone wiring wrapped around old 110v wiring? maybe? or who knows what kind of weird leakage/ground loops may have existed)

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Quite a few years ago, I spent many hours making my way up the support tiers at Time Warner in Brooklyn to resolve some connection issues (cable modem). I patiently waded through each tier as they repeatedly asked me to reset my modem and my router and restart my computer and check every cable, etc. The same things I'd already done before (as an on-site tech myself, at the time) and as the previous support person asked me to repeat.

Finally I made it to tier three, with someone who seemed obviously competent. Within about a minute, he checked the power usage on my modem and then historically, and knew immediately that if I moved my modem to another outlet, it would work.

It did. Never had that type of connection issue again.

This happened to me as well, only with DSL. The strip lights on the bathroom mirror (newly installed) would disconnect the internet when turned on.

Such a weird thing to troubleshoot when you have a few people living in the same house.

cheap AC to DC power supplies are very 'noisy' in the RF spectrum.

At a very former workplace, we suddenly lost the ability to ARP between two buildings. Once the ARP entry was in the machines, it worked fine (FSVO "fine"), but getting to the point where ARP worked simply was not reliable.

Much troubleshooting later, it turns out that when they'd been doing some maintenance in the lift shaft (which was also used to drop the inter-building 10Base-5 yellow snake), they'd managed to shoot a nail through the Ethernet cable and we now had a nice 50Hz hum on the cable.

Retries in TCP made that work, but ARP doesn't have retries, so if that managed to get faded out, you'd hope to get lucky next time...

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