"Attempt to ignore" Great question. So it uses hardcoded values of 8.8.8.8/8.8.4.4, unless it can't contact them by testing to resolve connectivity-test.google.com (or something like that), if it can't then it falls back to the DNS servers provided by your DHCP server/router. So to use smartdns with chromecast you have to both set your router to provide the SmartDNS servers and also blackhole 8.8.8.8/8.8.4.4 on your shitty ISP router (iirc static routes) - conspiracy? - i'll leave that to you? (the smartdns route is necessary since chromecast don't have their own VPN facility)