-    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"


Since android TV 14:
On Android TV, go into Developer Options and turn on Wireless Debugging (not USB).
Under Wireless Debugging, select "pair device with pairing code". Note the IP Address, Port Number, and Wi-Fi Pairing code shown.
On your PC, run a command to pair adb with the Android TV: adb pair <IP>:<port>. Enter the pairing code.
Connect to the now-paired Android TV using the IP address and port number shown on the Wireless Debugging page. This port number will be different than the port used during pairing, and periodically changes! adb connect <IP>:<different port>
Then follow point 5 up