I am running a Pi-hole on a Raspberry Pi 4 to provide ad-blocking for specific devices on my home network, rather than deploying it network-wide via DHCP. My primary router is a Verizon CHR30A Wi-Fi 7 Router, and I have a secondary CHR30A acting as a mesh extender on the second floor.
I manually configured the Pi-hole's IPv4 address in my iPhone's Wi-Fi settings. I expect the iPhone to use the Pi-hole for DNS resolution seamlessly as I roam between the primary router and the mesh extender.
Operating System: Raspberry Pi OS (Raspberry Pi 4)
Hardware: Raspberry Pi 4, Verizon CHR30A Wi-Fi 7 Router/extender
Actual Behaviour:
When my iPhone is connected directly to the primary CHR30A router on the first floor, DNS resolves through the Pi-hole correctly and ads are blocked.
However, the moment my iPhone roams and connects to the secondary CHR30A mesh extender on the second floor, the ad-blocking breaks.
If I set the verizon router to use pihole as a dns server for broadband connection, I am unable to ping google.com on my pc, and my phone cannot load google or other sites anymore.
This did not happen when I used pihole on an eero network connected to the verizon router.
I have tried turning off ipv6 on the router settings page, pihole with and without ipv6 upstream, dummy ipv6 dns ::1 on iphone and I am at a loss.
What do your SSID names look like on both units and what is the IP Address range on both ?
If the SSID names are different I can imagine the phone using a different profile to connect to the secondary unit and also apply different settings to it...
Are you also 100% sure the secondary unit is in Accesspoint Mode and not Router Mode ?
The SSIDs are the same. The Verizon settings page calls it an extender 192.168.1.100. The wifi range for the router itself is 192.168.2-254. I think they share the same ip addresses between them.
You need to know for sure because otherwise Pi-Hole sees it as a non-local connection unless you select "Permit All Origins" in the Settings/Configuration
2.1 Expanding Wi-Fi coverage
Connecting one or more Wi-Fi Access Points that function as extenders to a Wi-Fi Access Point that
functions as a router allows you to extend the Wi-Fi signal range and eliminate Wi-Fi dead zones in your Wi-Fi
network.
Refer to the self-setup flow in My Verizon app or Verizon Home app.
Sad... ...
Pretty good features for a device that's handed out to customers by an ISP though
Not everything you would want it to have, but a lot more than most of the stuff that I have seen!
And they seem to give each customer a seperate ONT so you can always connect your own Router + all other network devices if you want!
... 
