There are many reasons why you might want to check if someone is using your Wi-Fi network without permission…
It may have already happened and you usually understand it from the speed of the wi-fi connection that starts to "crawl." Of course, we should also mention the consequences for the security of your data, as an experienced and malicious user can somehow gain access to the files on your network.
Check the devices connected to your router
The first thing you need to do is log in to your router's management console by typing the IP address in the browser's address bar (usually: 192.168.0.1 or 192.168.1.1 depending on which router you are using. If you don't know the default address of your router, go to the command line from
Start/Run/Search for cmd run the exe and type ipconfig. The address should be listed next to the Default Gateway of your local network.
Alternatively, if you are using a Mac, you can find the default address by going to Network under System Preferences. The IP should be listed right next to “Router:” if you are using Ethernet, or by clicking “Advanced…” and going to the “TCP/IP” tab if you are using Wi-Fi. Then, type the address into your browser and you will be asked for your login details – if you have not changed the default settings, the username and password should be on the back of your router. If you cannot find it, download this file containing default usernames and passwords (PDF). Alternatively, you can search here, or here, or search for it on Google. We recommend changing the username and password immediately.
Once you have a look inside your router's management console, look for a section that will show you the connected devices or the wireless status. On the router we used, we found the list in the DHCP Clients List section. Sometimes it is available from the Status/Wireless path, and you will find it as "Attached Devices".
Check the list to see if there is an intruder among the devices listed. You can find the MAC / IP address of your computers from the Command Prompt by typing, 'ipconfig /all' The MAC address will be displayed as a physical address.
What do I do next?
The best and simplest solution is to create a strong password using WPA2. WPA – WEP encryption is very easy to crack and should be avoided if possible. There are some other methods you can use to enhance your security, such as disabling SSID broadcasting (this prevents your network name from being displayed to nearby devices searching for Wi-Fi), or setting up a filter to be able to block devices by MAC address. This will not stop an experienced attacker, but it will slow them down.
The above steps should be more than enough for most users to secure their wi-fi, but if you really need to find out who has hacked your network and locate their physical location, you can use a tool called MoocherHunter. You will need to burn a Live CD and boot your computer from it. From the Live CD, you will be able to locate all unauthorized users of your wireless network. According to the program’s description, it detects traffic sent across the entire network and can find the source with an accuracy of 2 meters.
MoocherHunter is included in OSWA Assistant.
Alternatively, you can use the Wireless Network Watcher app. It will alert you with a sound whenever someone connects to your wi-fi.
