Chromecast Ultra does not work if 8.8.8.8 is blocked

[smartfly101]

Hello everyone!

I got myself a Chromecast Ultra (Stadia Edition).

I am using a DNS Filter at home that blocks ads and other nasty stuff I dont want my kids to see.

Therefore I prefer all devices at home to use MY dns servers.

I blocked 8.8.8.8 and 8.8.4.4 so devices in my home wont try to use other DNS servers.

What I did not expect was that Google (intentionally) hardcoded their DNS Servers into the Chromecast and made it mandatory for the(ir) device to use those … and if not accessible, turn the device into a useless device!

So the CCU will not cast anything if 8.8.8.8 and 8.8.4.4 are blocked, outright playing dead. 

Does anyone know how to disable it or at least make the CCU use my own DNS servers? 

[WebServicesG4]

I might have similar issue. I am located om a guest wlan where only dns queries are allowed to the dns forwarder which is propagated vian DHCP, no other DNS is allowed to be queried. This brings the device to say 'not able to connect to the network'  and makes it unusable for my purpose ( mirroring PC to HDMI display ).

I claim this a bug as I seldom worked for customers allowing DNS queries outside their network directly

[Xenir]

Yeah, I have encountered this with the Nest-mini and Nest-hub. I have blocked all DNS traffic except to two local piholes in the network, which in turn use the Pfsense firewall as a forwarder. I have tested by allowing one Nest to access 8.8.8.8 and it started to work again. I find it outrageous that Google decides which DNS server I should use, and completely ignores the one set via DHCP.

In the end I have used a redirect rule to redirect UDP traffic to the Google DNS servers to the local firewall. In case any one with Pfsense tries to do this, see their documentation.