1. Check The Device Router List
This particular list can be found inside your router’s administrative console, which can be accessed by logging into the router console. In order to do that, you can simply enter your router’s IP address into a web browser window. Once you are in, you should look for a page that’ll show you all the devices connected to the network.
All routers are different, so the page might be named differently on different router console. Just try and look for something like ‘Device Manager’, ‘Connected Devices’, etc. The page should give you a list of IP addresses, MAC addresses, and device names. Just compare them to your devices to see if you can find any unwanted devices.
Alternatively, you can also use network monitoring tools on your computer to find out unwanted devices that are connected to your network. Most of these software tools will also offer some advanced features to get more control over your network. Before downloading a third-party tool, you might want to confirm if your router comes with its own software. A lot of companies like ASUS, D-Link, Netgear, etc. all have their own network management apps.
2. Checking The Router
One of the easiest ways to find if someone is stealing your wifi is to check the lights on the router itself. You may have noticed that there are a bunch of lights on your router. Well, they show internet connectivity, hardwired network connections, and also any wireless activity.
So the first thing you might want to do is disconnect all your devices from the network and see if the light indicating the wireless activity is still blinking. If it is, then you can be sure that someone is mooching your wifi. But with this method, you sadly can’t do anything else. It’s just a quick and easy way to confirm your suspicions.
How To Stop Them From Stealing
Once you know that someone is indeed stealing your wifi, the question is - "How to stop them?"
Well, the first thing you should do is to check the security protocol used to protect your network. Make sure you're avoiding old security protocols like WEP and WPA, and are sticking to more modern protocols like WPA2-AES. A quick Google Search about the protocols should give you more info.
And the next thing which we'll suggest would be to use a strong password. And not just that, it's important that you keep changing your password once in, say, 2 months to keep intruders away. That way, even if someone manages to crack your wifi password, they'll be kicked out every 2 months, eventually forcing them to quit being cheap and get their own connection.