OpenDNS is a great service and works well with my 3-unit eero setup. Easy to configure - just enter the 2 DNS server addresses in eero app's Network Settings > Advanced > DNS. It's not clear to me what would be gained by the original poster's suggestion to offer OpenDNS during the initial eero setup.

The process for changing your DNS settings varies according to the operating system and version (Windows, Mac or Linux) or the device (DNS server, router, or mobile device). This procedure might not apply for your OS, router, or device. For authoritative information, see vendor documentation. How to Set Up OpenDNS on Your Wi-Fi Router Dec 19, 2019 OpenDNS Test: Check if OpenDNS is Working

Find the DNS server settings. Scan for the letters DNS next to a field which allows two or three sets of numbers, each broken into four groups of one to three numbers. Put in the OpenDNS server addresses, and, as your DNS server settings and save/apply. Linksys Router. Visit the router's IP address in a new browser

Best free and public DNS servers in 2020 | TechRadar Jun 18, 2020

Jun 01, 2014

NETGEAR Live Parental Controls - Sign in to your OpenDNS Use OpenDNS Parental Controls with your router to make the Internet safer for your household. The Netgear Dashboard now uses the OpenDNS Login page for enhanced security. Click here to learn more. OpenDNS - DD-WRT Wiki OpenDNS is a free DNS (Domain Name Server) service which makes internet browsing safer and allegedly faster. By simply using their DNS servers instead of your ISP's you are automatically protected from their list of Phishing websites. However, in order to restrict a variety of adult website content you will need to create a free account with them, register your IP address and select the OpenDNS Integration - Discussion Topics - eero Community