Neighbours Router somehow being used as my DHCP

[AC199]

My apologies if this seems to be in the wrong forum, but I believe this to be the right place, given the nature of this issue this is both information gathering and questions...

I am on the Fibre 150 service and have a good line to my house, happily connects at 140mb down and 30 up.  I also have my network at home, I run 2 powerline adapters, a modem, TP Link Router and many devices on both 2.4, 5ghz WiFi, but predominantly via ethernet (My hatred of WiFi is well documented). DHCP is controlled via my router on the subnet 192.168.0.X. I moved to a TP Link AX20 and Modem after these issues started.

My neighbour is running a HomeHub 6 and has a 20mb connection (the cheapest offered basically) and I have never joined that network in any way shape or form, I have no idea what the Key is, never tried to join the network either via wifi or ethernet. 

I've had a fault open with BT now since 1st October and it has yet to be resolved to my satisfaction. 

For some reason, when I connect to my wifi SSID or via ethernet with DHCP enabled, I get given an IP in the range of 192.168.1.X even though my router operates on 192.168.0.X. When I access the admin page for the router I can see his SSID, and can interact with the router, calling up devices connected etc and see my phone, my wifes phone, our Smart TV all using his router as DHCP, even though all devices are either ethernet connected to my router, or WIFI connected to my SSID via my TPLink router, yet I get a Smart Hub control page.

I can temporarily clear this by rebooting my router and refreshing my IP on ethernet devices, but I'd like a more permanent solution than that.

Anyone seen this before? I'm confused as hell. I originally thought it was an IPV6 issue with the smarthubs which is why I'm using a TPLink, but clearly that isnt the issue given IPV6 is disabled on my network.

Could this be an issue with the WAN side of things? Maybe a crossed connection at the telegraph pole or something?

I'm pretty close to just smashing his router to bits and giving him one of my spares, but I'd like to avoid that since its BTs property and not his per se.

Thanks

Chris

[licquorice]

I suspect your neighbour also has powerline adapters and is possibly on the same electrical phase as you are.

Simple to verify, disconnect your powerline adapters temporarily and see if the problem disappears.

It can't be an issue with the WAN side of things.

[AC199]

He doesn't use Powerline adapters at all. I've already asked about that one.

Thanks for the response though. 

[gg30340]

How are you able to access the neighbour's Smarthub admin page. Are you entering a password?

[licquorice]

How do you know which hub you are connecting to, are you sure it belongs to the neighbour you think it does?  Does it belong to a different neighbour that does use powerline adapters.

I would still suggest removing the powerline adapters temporarily.

[AC199]

By entering 192.168.1.254 into a browser window, it gives the device name on the page where you land.

[AC199]

When all this started I asked him which was his SSID, he told me the name of it. That's the one I'm connecting to. It also shows up in my wireless networks list and given its 3 ft away from where I sit on the sofa the signal strength is as good almost as mine. 

[AC199]

Forgot to mention. I have tried removing the Powerline adapters and it didn't make a difference. 

[licquorice]

If you can connect to his WiFi without entering a password, he must have turned off WPA security. Simply get him to re-instate WiFi security to prevent your devices connecting to an open WiFi signal.

[AC199]

I'm not connecting to his wifi, not at all. I'm connecting to my router, with its own SSID, but for some reason his router is being used as my DHCP server and routing everything thru his crappy connection rather than mine. Somehow the networks must be mixing, that's what I'm trying to work out.