I don’t think this is a Pi-Hole issue but I couldn’t find anything while trying to Google. I have Pi-Hole set up in a Debian VM on my ESXi server as the DHCP server for my LAN. Everything works perfectly for wired clients. Wireless clients connect to the network via an ASUS RP-AC68U access point and this is where the trouble arises. Wireless clients get all the correct configuration from the Pi-Hole DHCP, but for some reason they do not actually use it for DNS queries. Local name resolution doesn’t work, and ads are still displayed, however I’m still able to access the internet.
Now, the AP itself is configured correctly, it has some network troubleshooting tools built in, one of which is nslookup. Testing resolution with this works every time, but just to be sure I also tried manually setting the AP’s DNS servers to the Pi-Hole but experienced no change with wireless clients. I’m pretty confident the AP is doing something whacky here, but I don’t know where else to go or what else to do to troubleshoot.