How To Check if Someone is Using your WiFi

Posted by Jamie on May 15, 2018

Is your WiFi network running slow? Have you been sent a copyright troll letter when you know it wasn’t you? Your wireless network may have been compromised and could be being used by someone else right now. Here is how to check if someone is using your WiFi.

Internet access is cheap but that doesn’t stop people wanting it for free. If you’re planning to do something illegal online, what better way to cover your tracks than leach of someone else’s network? That could be downloading pirate content, hacking or whatever.

Knowing who is using your WiFi and when is paramount to running a secure network. This tutorial will show you how you can check if someone is using your WiFi, how to kick them off and how to stop it happening again.

Check who is using your WiFi network

There are a couple of ways to find out if someone is using your wireless network. The easiest way is to look at the activity lights on your wireless router. Turn off all devices in your home and see what happens with the wireless activity light. If it shows a lot of activity and there is nothing else in your house using it, this could be a sign.

If you suspect something, log on to your wireless router and find out. Depending on your router, there should be a page that shows a list of connected devices. In a Netgear router, this is listed as Attached Devices under Maintenance. In a Linksys Smart Router it is listed under Network Map. Other routers will likely have their own nomenclature.

  1. Log into your router.
  2. Navigate to Network Map, Attached Devices or whatever.
  3. Identify each device listed.

If you have trouble identifying all the devices listed, turn devices off or disable WiFi and refresh the map. While a process of elimination, it should identify all devices after a while. Don’t forget to include smart TVs and any IoT devices you may have. If you are left with an unidentified device, it may be someone outside your property.

There are also third party tools that can help. One great tool is the F-Secure Router Checker. Visit the website, select the blue Check your router button and let the website do its work. It will assess any vulnerabilities in your router and alert you to them.

WiFi Inspector is a Google Play app that scans your WiFi network and tells you what devices are using it. It is a good way to identify devices accessing your network.

Secure your WiFi network from intruders

If you do identify someone piggybacking off your wireless, it’s time to remove them and stop it happening again.

I use a Linksys Smart Router so my instructions describe that. Your router may differ slightly and use different terminology. Just adapt the following to your specific model.

  1. Log into your router and access the admin interface.
  2. Select the Wireless part of the interface or find Guest network.
  3. Turn off the Guest network unless you specifically use it.
  4. Turn off wireless. On a Linksys router, this is a toggle. This will kick everyone off your WiFi.
  5. Select WPA2 as the wireless security mode if it isn’t already selected.
  6. Change the wireless access password and save changes.
  7. Enable wireless once more.
  8. Change the password on any devices that connect to WiFi.

Turning off wireless will kick off all users at that time so you may want to schedule this to avoid disruption. Once off, make sure to use WPA2 as it is currently the most secure encryption around. Change the password to something as difficult as is practical while still being able to remember it. Mix upper and lower case, letters and numbers. If your router allows, throw in a special character or two for good measure.

Extra steps you can take include disabling WiFi protected setup and upgrading the router firmware. There should be a setting in the wireless part of your router that disables WPS. This is a known vulnerability in shared properties, dorms or other places where there is no control over who comes and goes. Turn it off to stop people being able to authenticate on your network.

Upgrading router firmware allows your router to benefit from any security patches or fixes. The recent KRACK vulnerability is a case in point. It found a weakness in WPA2 which was quickly patched out. Only a router firmware update can fully protect you, so allow automatic updates on your router if it is possible, otherwise check regularly for updates.

That’s how to check if someone is using your WiFi and how to stop them. Got any other ways to achieve that goal? Tell us about it below if you do!

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