If you think someone is using your Wi-Fi network without permission, you probably need to work on your Wi-Fi security – a well-secured network is pretty hard to crack. To confirm your suspicions, though, you’ll need to check your network and see what’s going on there.
The best way to do that is usually to access your router’s management panel. If you don’t have access to the router web interface, perhaps because you’re checking a public network or possibly scanning an Airbnb for carelessly hidden cameras (not a guarantee, since a smart voyeur would put them on a hidden network or use a memory card), your best bet is to get a program or app that will scan the network for you.
Check Your Router’s Web Management Interface
To get the most detailed information about the devices on your network, you’ll have to get into your router’s web interface – the same place where you can change the network name, password, and do other administrative tasks. You can usually do this by typing an address (usually 192.168.0.1, 192.168.1.1, 192.168.2.1, or 192.168.1.100) into your browser bar. Googling your router brand or looking at the device can usually help you figure out which one to go with.
After that, you’ll need to log in to the router using either the default information printed on the device or whatever you changed it to. (Changing it is a smart move since most routers come with default settings like “admin” and “password.”)
Once you’re in, look around for an option called “Connected Devices,” “Local Network,” “WLAN,” or anything that looks as if it might give you information about your network. This will vary by router manufacturer. The logs may also be hidden behind a button or menu that shows you information about DHCP clients.
You’ll know you’ve found the right place when you see a list of currently connected devices that probably give you an option to see logs of past activity as well. You’ll pretty much always see a MAC address, and depending on your router manufacturer, you may also see an IP address, a device name, or other information. If you know the MAC addresses for every device that is supposed to be connected to your network, you can just compare the list to your router’s logs (if they’re accessible) to find out what’s been going on.
Easier Option: Use a Network Scanning Tool
If accessing your router and comparing MAC addresses isn’t really your cup of tea, there are tons of programs available to help you monitor your network. They won’t usually show you detailed logs the way your router can (unless you set them to automatically scan and collect data every few minutes), but they can tell you what’s going on in your network at any given time, and some of them can do much more. They’ll also usually give you information about a device’s manufacturer, which can make it easier to figure out what you’re seeing Most of them are quite easy to use – just download, run, and scan your network.
Nirsoft Wireless Network Watcher (Windows)
This program is simple, free, and effective. It scans your network, tells you the addresses and details about connected devices, and even keeps track of how many times it’s detected these devices, perhaps allowing you to catch suspicious activity with regular scans.
Who Is on My WiFI/WhoFi (Mac/Windows/Android)
Intended for use with a larger-scale network analysis and optimization package, this program can also just be used for free as a personal network scanner. It should show you most vital information about the devices on your network and even allows you to set it to automatically scan your network at certain intervals and collect data about the devices on it.
Advanced IP Scanner (Windows)
Advanced IP Scanner tells you all the basics about who is on your network, nothing new here, but is extra useful if you’re looking for tools that help you remotely access and manage devices on your local network.
If you want a nice, smooth mobile experience, it’s hard to beat Fing. It gives you quick, clear results and comes with some analytics tools if you’re interested – a great way to do a quick network check.
Angry IP Scanner (Windows/ Mac/ Linux)
Despite the name, using this program isn’t likely to make you very angry, as long as you’re a bit of an advanced user. The interface is slightly less straightforward for people who may not be familiar with networking, but provides a lot of advanced functionality if that’s something you need.
Using Command Prompt (Windows)
Another way you can check devices currently on your network is using the command prompt, though this method is a little less straightforward and doesn’t give you a lot of information. Simply open command prompt and type in
arp -a. This will display a list of IP and MAC addresses. To find out the device names associated with an IP address, type
ping -a <Insert IP Address>.
Using Nmap or Nutty (Linux)
If you’re a Linux user, you can use the popular network analysis tool Nmap to identify devices on your network, following the instructions available on the tool’s main site. Alternatively, you can try Nutty, currently available on Elementary OS and Ubuntu.
Why Would I Care About This?
Unless you’re trying to optimize and manage a large network, you probably won’t need to do this on a regular basis. Nonetheless, it’s quick and easy if you’re curious about your network or suspect unauthorized use. It might help if you want to figure out which devices are causing problems. It could also be that you’re just lazy and want to find out the MAC address of that machine across the room without getting up and checking. Work smarter, not harder, right? Worst-case scenario, if you do find someone using your network, it’s time to read up on Wi-Fi security.