Tag: powerline

A few days ago I was sitting at my computer as I do and saw this in windows explorer…

I was a little confused, I live alone and only have a handful of devices connected to the internet, none of them called mark.

I checked my DHCP and found nothing, just me and my phone online.

I remembered that I recently connected to the work VPN and maybe windows was remembering some of the devices I was connected to, one of the guys in Infra is called Mark, so it was probably his laptop and windows was just remembering it, at the very least nobody was on my network… right?

So a day goes by. I notice again in windows explorer, my laptop is not online, but my PC and Mark are, not only is Mark still connected to my network, but I know for sure my network has refreshed recently. The plot thickens!

I again checked my router, no other devices connected.

A week or so goes by, my network keeps playing up, having dropouts, devices not connecting to one another general laggy behaviour, Mark is still there.

One day I’m playing CS:GO and my connection drops out, third time this week. I go to check my router settings. Type in username and password “This password is incorrect”. Try it again, “This password is incorrect” I double check the IP to make sure I’m still in the right place. Then it hits me; my router doesn’t ask for a username, just a password.

I was seeing this:

But should have been seeing this:

My usual login screen

I checked on my phone, connected to my router first time. Checked the DHCP and noticed something odd. I wasn’t there. My PC just was not connected to my network. So I thought I would check, and lo and behold

My PC and the rest of my devices were on 2 separate networks. So what’s the difference, well my PC has a wired connection but instead of connecting direct I use powerline adapters, articularly I have these powerline adapters. Powerline adapters use your homes internal wiring to transmit data packets around the place, as to not interfere with regular electricity they broadcast on different frequencies.

So I thought, what if a neighbour has the same adapters I have, or ones using the same frequency. The connection at my end wouldn’t know who it was paired with, it would connect to both or switch between them depending on who it decided to pair with. Now it made sense, the slow internet, the timeouts wasn’t my service being shit. I was connecting to another network altogether!

I decided to conclude my findings, on this new network I decided to have a bash at their router password, most people aren’t me and don’t change their default password, and since it was a Virgin Router I knew what that’d be. Unsurprisingly I gained access straight away, went to their DHCP page and would you believe it

Mark was never stealing my internet, I was stealing his! it also meant, more worryingly, that the electricity in my house was not a self contained network, the sockets on my PC are somehow connected to another houses power supply.

I was so impressed by this problem I thought I would share it, as I’m simply fascinated such a problem could exist.