1. Connect a device, such as a computer or tablet, to the internet through WiFi or using an Ethernet cable connected to your modem.
3. Log in to your modem's online settings interface (Modem GUI) using your Administrator Username and Administrator Password. Unless you have changed the default settings, you can find this information on the modem's sticker. Note that these are different from your wireless SSID and security key.
4. Select "Wireless Setup."
6. Select "MAC Authentication" in the menu on the left.
7. Select your wireless network (SSID). Your active network will usually be the one at the top of the drop-down list.
8. If you are setting up MAC authentication, select "Enable."
9. Set the list type to "Allow" or "Deny." This determines whether the MAC addresses you enter in the next step will be allowed to access your network or forbidden.
10. Enter the MAC address (or select a device from the drop-down) that you want to allow deny, depending on the "list type" set in step 9.
11. Select "Apply" to save your changes.