I really enjoy using Pi-Hole. Unfortunately since three days I am running in big trouble (while I thought I did not change anything)!
I am using Pi-Hole as the only DNS server in my network. It shall forward all requests to the Mullvad DNS (188.8.131.52). In my network there are two VLANs, one is using Mullvad VPN, one is not. This setup used to work perfectly since the pi-hole is in the VLAN not using Mullvad, but access is allowed for the other VLAN via a routing rule. I am using OpenWRT on a TPLink router. On there I have chosen the pihole Ip (192.168.100.2 in my case) as forwarding address in DHCP and DNS settings and also as Custom DNS server in Interface “WAN”. There is no other DNS configured anywhere.
When I start the router it shall connect to Mullvad VPN, update the time and the dyndns. This requests are send to the pi-hole.
All this is not possible since three days. The router’s syslog is telling me that servers like dynupdate.no-ip.com could not be resolved from the router. The question for this is send to the pi-hole. I see the questions in the pi-hole but it does not to answer. All other members in the network are working fine. In the moment I add “184.108.40.206” in the DNS forwarding option of the router it connects to mullvad and let me surf perfectly. I can delete the option afterwards. Then I see in the OpenWRT syslog that all requests are send to the pi-hole as should and also are aswered. Blocking works too (tested with facebook).
I also experience messages like “Rejected request from RFC1918 IP to public server address” when I try to contact my nextcloud via dyndns name running in the same network. This was working before. I also experience a lot more PTR messages than before in pi-hole log.
I tried many things in OpenWRT and also opend an issue in their forum (https://forum.openwrt.org/t/router-can-not-resolve-dns-requests-but-rest-of-network-can/52591/14) without success. So I went back to an old OpenWRT config which was running perfectly. Same behaviour. Since I see the messages going to the pi-hole I guess the problem might lay there. I upddated two days ago, and also tried repari without success. Can you help me here?
I could not upload the output to tricorder: "
[✗] There was an error uploading your debug log."
Here it is nevertheless:
Output_PiHole-d.txt (20.5 KB)