1. Connect a device, such as a computer or tablet, to the internet through WiFi or using an Ethernet cable connected to your modem.
2. Open a web browser and type http://192.168.0.1 into the web address field.
3. Log in to your modem's settings interface (Modem GUI) using your Admin Username and Password. Unless you customized this information, you can find it printed on the modem label. Note that these are different from your wireless network name (SSID) and password (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.