Networking – Neighbor stealing Wi-Fi


My Internet connection is slow and I am (almost) sure that the neighbor is stealing it. Whenever they are home, my Internet connection is slow. I logged in to my modem, but I am unable to find any strange devices in Device Manager. Is it possible that they are hiding on my network? I also notice that when I do a modem reset the Internet speed increases, but after a while slows down again.

Thanks for the input everyone, I am reading and writing down stuff I didn’t know about, appreciate it. I noticed my previous post lacked information so I decided to add the following:

  • OS: Windows 10
  • Modem: Huawei hg 659 (provided by ISP, no additional router operational)
  • ISP: T-mobile home DSL

I switched off all devices at home unplugged everything and shut down all mobile devices. The WiFi and LAN lights keep on flashing and won’t stop. I still have to try the cable method. During the day I have to work from home so I can’t do anything till the weekend. I will keep monitoring for further information and advice.

Best Answer

The other answers so far are about security, but there is another factor that may well be at least part of your trouble.

A wireless network at 2.4 GHz (in Sweden where I am, using b/g/n) allows 13 channels. (My router also has an "auto" setting.) On top of that, if the router has 5 GHz Wifi there is another set of channels.

I suggest you download e.g. Wifi Analyzer or any similar app into your phone, and use it to check which channels are most used - disregarding your own router [check which channel it uses in the "WLAN settings/setup"].

Now; Avoid those channels!

Look up any channel that is among the least used, and set your router to that - or possibly "Auto" if there is one such setting; assuming it wasn't set while you've had trouble.

Note: move about in your apartment / house and check in different locations. You might discover that the signal strength is weak where your computer is - related to the router (remedy: move the router and computer closer to each other; avoid having walls between).

Possible root cause:
If your router uses the same or a neighboring channel as any other nearby router - then your throughput will be lessened by "collisions", the more intense use, the more of it.

One more thing to think of:
If you have a lot of devices running on WiFi - and many in use at the same time; this itself may become a problem. "A lot" of active users might create such an amount of traffic that you get congestion i.e. WiFi "traffic jam".

Worth mentioning:
A microwave owen uses 2450 MHz to create the heat. This is inside a Faraday cage though - shouldn't leak much, normally.
Bluetooth devices on the other hand has more potential to cause trouble - as the frequencies used in that radio are the same as for WiFi.
The ISM Bands include the same frequencies, many more device appear here. (e.g. cordless phones, wireless headphones, car keyfobs, security cameras, zigbee devices, remote control devices(?), ...)
Yet another Wikipedia article covers the technicalities, which include some details that, to some extent, also laymen could understand. The Interference section might be of interest for anybody. Detail; Wifi uses "CSMA/CA" in contrast to "CSMA/CD" for wired networks.

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