Hi,
I'm experiencing a strange issue with my recent Pi-hole implementation.
It runs on an Orange Pi PC with Armbian, core version is 6.1.2, 32Gb SD.
I found that when Windows clients are configured with Pihole as the only DNS server, DNS stops resolving for about 5 minutes. Only happens during Windows startup (I tested with 2 different Windows 11 clients), and digging google.com @pihole.ip causes a timeout on DNS on the Pihole terminal.
I have a special configuration; my Ethernet card has two IP addresses, one for OpenVPN running on UDP 53 and the other for Pi-hole DNS, of course, on UDP 53. OpenVPN works fine, and Pihole too, until I boot a Windows computer. I can not say if it happens with mobiles or other devices because adding a second DNS server mitigates the issue, and I configured another DNS server on DHCP.
I tried disabling OpenVPN, adding another subinterface, another physical interface... but this was driving me nuts. Until I saw this post: [RESOLVED] Core 6.0.5: DNS Times Out || Multi clients || Excessive DNS queries || High CPU ||
So, today I did a test and... bingo! As soon as I boot the computer, one core goes to 100% and DNS resolution fails
Looks like this bug appears again. Disabling filtering resolves the issue too, at least during startup. After a while, I can enable filtering again, and DNS keeps running.
DNS service never stops, simply doesn´t respond.
How can I resolve this?