Pi-hole and OpenWrt setup (IPv6 issue?)

[tsengf]

Hi, I have a fairly vanilla setup of Pi-hole on a RPi and OpenWrt on a router. I've set up OpenWrt using method 2 from How do I configure my devices to use Pi-hole as their DNS server?. However, ads are still not being filtered. Upon looking at the DNS servers of a client, I see the following entries

IPv4 DNS servers: <IPv4 address of pihole>
IPv6 DNS servers: <IPv6 address of router>

I suspect the second line is causing DNS resolution to go to the router instead of the pihole. How can I fix this? Thanks.

[smurf]

On your router, replace IPv6 address of router with IPv6 address of pihole or disable IPv6 altogether.

[tsengf]

I was able to resolve this issue by unchecking "Local IPv6 DNS server" to prevent OpenWrt from announcing itself to the clients.