Blocked that hard-coded google dns garbage.
I have a firewall rule to dst-nat any outgoing DNS requests not coming from piHole back to the piHole server. That way all devices on the LAN are forced to use piHole for DNS and can’t bypass it. I don’t have an OPNSense firewall but I would think it should be able to do that as well.
Is this to block ads?
No, you can block ads with a pihole. This is because Roku hard codes its dns server as 8.8.8.8. Pihole doesn’t handle IP addresses, only DNS.
Interesting. I set an adblocking dns via DHCP and, as far as I know, the Roku respects it. Ads are blocked and I can see it failing to delivery telemetry in my dns logs (most persistent thing on the network).
I set a rule to catch outside dns to see if anything, the roku included, has been misbehaving.
Pihole blocks the basics for Roku. Things like logs ads etc. but there’s a lot more telemetry that they’re collecting. Here’s a hackernews thread about the topic and the associated article it references.