1. Launch the AirPort Utility.
The AirPort Utility can be found in the Utilities folder within your Applications folder.
Some users have multiple Airport Base Stations, select the one you wish to configure.
4. Change the configuration settings.
Click “Internet” to configure your router’s internet settings.
Enter 18.104.22.168 in the “Secondary DNS Server:” field.
Click “Update” to apply your settings.
To ensure that OpenDNS is working properly for you, please flush your browser and DNS cache by following the instructions below: