This is an old revision of the document!
Mikrotik and OpenDNS: https://www.phy2vir.com/configuring-mikrotik-to-use-opendns/
Mikrotik, Pi-Hole and OpenDNS: https://rickfreyconsulting.com/dns-filtering-using-mikrotik-pi-hole-and-opendns/
OpenDNS: https://support.opendns.com/hc/en-us/articles/227988047-Web-Content-Filtering-and-Security