This guide refers to the GFRG100 but should apply to most current models.
This device cannot be configured for custom DNS servers such as OpenDNS at this time. To use OpenDNS on the network for this router, you would need to use a second router on the network and configiure the Google Fiber device using the following instructions: https://support.google.com/fiber/answer/2446100?hl=en&ref_topic=2731870. Please note that if your router is not a gigabit router, you will lose 9/10ths of the maximum speed of your Gigabit Fiber connection.
Without using your own secondary router, you may choose to configure your computer or devices individually.