-    Go to Settings and enable Developer Mode on your Chromecast with Google TV.

-    Enable USB Debugging

-    On your PC, install adb and type "adb connect $IP_of_chromecast"

-    Allow the connection from your PC on the chromecast

-    Type "adb shell"
     Type "settings put global private_dns_mode hostname"
     Type "settings put global private_dns_specifier nsec.arnor.org"

note:  to disable Private DNS: "settings put global private_dns_mode off"