Once you’ve given someone your Wi-FI password, they have unlimited access to your Wi-Fi, and they can join your network on all their devices. That’s how it usually works, anyway. Here’s how to boot them off.
Option 1: Change Your Wi-Fi Password
The easiest, most secure method is merely changing your Wi-Fi network’s password on your router. This will forcibly disconnect all devices from your Wi-Fi network—even your own. You’ll have to reconnect to the Wi-Fi network by entering the new password on all your devices. Anyone who doesn’t have your new password won’t be able to connect.
Let’s be honest: If you have a lot of devices, reconnecting them all will be a pain. But it’s also the only real, foolproof method. Even if you’re capable of blacklisting a device on your router so it can’t reconnect, someone with your Wi-Fi password could connect on a new device. (And, even if they don’t remember the password, there are ways to recover saved Wi-Fi passwords on Windows PCs and other devices.)
To do this, you’ll need to access your router’s configuration settings—usually in a web interface—sign in, and change the Wi-Fi password. You can change the Wi-Fi network’s name while you’re at it, too. We’ve got a guide to accessing your router’s web interface, and you can also perform a web search for your router’s name and model number to find the manufacturer’s manual and official instructions. Look for a “Wireless” or “Wi-Fi” section in your router’s options.
This all assumes you’ve set a password on your router! Ensure you enable secure encryption (WPA2) and set a strong passphrase. If you’re hosting an open Wi-Fi network, anyone will be able to connect.
RELATED: How to Change Your Wi-Fi Network’s Name and Password
Option 2: Use MAC Address Filtering on Your Router
Some routers have access control features that can manage which devices are allowed to connect. Each wireless device has a unique MAC address. Some routers let you blacklist (ban) devices with a certain MAC address from connecting. Some routers let you set a whitelist of only approved devices and prevent other devices from connecting in the future.
Not all routers even have this option. Even if you can use it, it’s not entirely secure. Someone with your Wi-Fi passphrase could change their device’s MAC address to match an approved one and take its place on your Wi-Fi network. Even if no one does, you’ll have to manually enter MAC addresses when connecting new devices or an attacker will just be able to connect at any time—it doesn’t seem ideal.
