How to tell if someone is stealing your Wi-Fi — and what you can do about it

Think someone's leeching off your Wi-Fi connection? Here's how to find out

If your internet has been unexpectedly slow lately, someone living nearby may be stealing your Wi-Fi. There’s only a certain amount of bandwidth to go around and if yours is already divided up between a few computers, a smart TV, and a couple of phones, there’s a good chance you’ll start seeing slower speeds when an internet freeloader streams a high-definition video.

You don’t want any unauthorized devices tapping into your Wi-Fi, both because of the performance issues it causes and the big security risk that it represents. So if something funny is going on with your Wi-Fi, it’s important to check it out and fix the problem (while ditching the moochers).

Is someone stealing your Wi-Fi?

If you only have a few Wi-Fi devices in your house, you may want to unplug or turn them all off, and then watch the wireless signal light on your router. If the light continues to flicker, someone else is using your Wi-Fi.

However, this method only works if you can be sure that every wireless-capable device you have is powered down, which may not be easy to do in many homes. So, we present two in-depth methods for checking for Wi-Fi thieves, no matter what setup you have. If you need a refresher on wireless networking itself, then check out our Wi-Fi overview.

Method 1: Use an app

A number of apps are available to provide automatic searches for unusual devices logged into your Wi-Fi network. Checking those devices, especially if they’re connecting at odd times of day when no friends are over, can provide valuable clues. Here are a few apps that can help you pinpoint problems.

Wi-Fi Thief Detector extension: This Google extension is easy to download, and designed to produce fast results. It will show you how many devices are on your router, help you spot devices that don’t belong there, and connect you with your router settings so you can quickly make the changes you need to protect your router (see below for more information).

Paessler PRTG Router Monitoring: Paessler’s solution is a full suite of router management tools, including automatic detection of strange traffic, analysis of how the network is being used, and other in-depth tools. It may be a bit much for the average homeowner worried about their neighbors, but it’s an excellent tool for small businesses concerned about someone hopping on their network without permission. We suggest you stick with the 30-day free trial, which should be enough to root out any problems.

F-Secure Router Checker: F-Secure is a web-based tool that is useful if you want to avoid any downloads. This tool checks for more serious hacking — specifically, it looks for signs that someone is using stealthy setting tweaks to hijack your internet, which may be useful for tougher cases.

Wireless Network Watcher: This independent software is designed to help Windows and MacOS users watch for suspicious wireless activity and monitor all currently connected devices.

Fing: Fing is an iOS download for more mobile-oriented protection. It allows you to immediately see connected devices, what type of devices they are, and the nature of their connection, MAC address, and so on. You can also check Wi-Fi connection behavior to note particularly busy times that could indicate someone else is hopping onto your network.

Method 2: Check administrator logs

If you suspect that someone is stealing your Wi-Fi, you need to log in to your router’s administration page. Most people can do this by typing 192.168.1.1 or 192.168.2.1 into the address bar. If these don’t work, swing on over to our guide for accessing your router’s admin panel.

Once you’ve accessed the admin page, you’ll need to locate the page listing the various Media Access Control (MAC) addresses connected to your computer. The location of this page will differ depending on your router, but you may find it under wireless configuration, wireless status, or in the DHCP client list. You can use this list to count how many devices are connected to your internet. If you see six MAC addresses — any device connected to your network will have its own unique MAC address — but only have four devices in your home, somebody is probably stealing your internet.

Note: Old phones, gaming consoles, Wi-Fi enabled cameras, and other connected devices may show up on the MAC address list. You can get a better handle on which MAC address represents which device by using a website like macvendors.com.

How to keep outsiders away

resetplug wifi router
123RF

If you suspect someone is stealing your Wi-Fi, it’s a good idea to beef up security (penalties for Wi-Fi theft vary greatly, so consult local law enforcement for follow-up). If you don’t have a password on your network, add one. If you still use the default router name and password, change it — you can do this from the admin page on your router.

To change your password, look for the pre-shared key in your security settings. Changing your wireless password will kick off all current devices (including those unwanted freeloaders), so you’ll have to reconnect your devices once you have a new password.

To change your router name, locate the Service Set Identifier. This is typically found in the wireless settings menu.

Lastly, it’s important to use the strongest wireless network encryption available for consumers. At this time, that’s WPA2, but it will soon be supplanted by a new standard, WPA3. If your router was manufactured prior to 2006, it may not be compatible with WPA2 encryption. If that’s the case, you may want to think about getting a new one.

Remove strangers on your Wi-Fi

how to tell if someone is using your wi fi tp link mac filtering

Sure, this is all great, but what do you do if you find strangers on your Wi-Fi and want to get rid of them? The easiest and fastest method is to simply change your WPA2 password to something longer and more robust. This will kick all devices off the network, allowing you to sign back and blocking people without the password. For casual moochers, this will be enough to deter further efforts, although you should still keep an eye on connected devices to make.

Otherwise, you can also look for an option on your router administration page that says MAC filtering, Device filtering, or something similar. This allows you to add MAC numbers to a list of blocked devices that your router won’t allow. Pick out the strange MAC numbers from unfamiliar devices, and add them to this list. This isn’t absolutely foolproof, as MAC addresses can be spoofed, but this would be pretty rare in situations like this.

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