first, I am really noobish regarding Linux. I just followed guides to install pi-hole and a local unbound DNS server. So please be patient, thanks.
Everything works fine with my actual setup. At least from my simple user perspective.
But every other day the pi-hole diagnostics throws up the error " Maximum number of concurrent DNS queries reached (max: 150)".
The query log shows that in that specific time my router (Fritzbox) floods DNS requests targeting the domain "dummy". In rare cases my TV tries to reach that domain, too. But the flooding is caused by the router.
Excessively repeated DNS request for unknown local hostnames (like dummy in your case) may hint at a partial DNS loop.
Your debug log shows you've enabled Pi-hole's Conditional Forwarding, which may close such a partial loop - if your router would be using Pi-hole as its upstream DNS server at the same time.
Did you configure your router to use Pi-hole as its upstream DNS server?
I've configured the static IP Adress (IPv4) of my Pi-hole as my preferred DNSv4 server. And - and that just came up - I might have misconfigured the DNSv6 settings. New router since a couple of weeks. I have to look into that.
Thank you for your quick replies and... sorry for my bad answer. I've read the linked article and it seems to be a similar issue? IPv4 seems to be fine here, but to be honest configuring ipv6 is currently hard to understand for me. And I am now sure I've configured that totally wrong.
So to get back to your question.
My router ist set like this:
The DNSv6 adress is wrong and advertisment ist currently disabled. Have to take care of that and the ULA setting is wrong. Have to find out how to correct that properly.
And if I get the term "upstream dns server" right: my pihole asks my local unbound server to resolve the DNS query. That's my setup so far.
Is your question now answered properly or is my answer still not helpful?
I've spent the last days reading and validating my setup. Seems to be fine so far until yesterday. Almost 3.000 DNS requests from my FritzBox within 15 Minutes. But this time not targeting for "dummy" but for "null".
Your debug log shows you didn't apply my linked advice yet (none of the filtering rules are present).
Since you are using Pi-hole as your FritzBox's upstream resolver and have Conditional Forwarding enabled, you have indeed configured a partial DNS loop.
Either point your FB back to your ISP's DNS resolvers, or follow the instructions to specifically filter some of your router's DNS requests from my linked post above.
Thank you for your patience and coming back to me.
Followed your advices now step by step. Sorry that I haven't directly.
Update: https://tricorder.pi-hole.net/e4xq8N0F/
The 3 new RegEx rules are currently disabled, my wife has an important meeting that I don't want to put to risk.
Question: would I achieve the same result, if I'd disable conditional forwarding and put all of my clients (with static IP) in /etc/hosts? So hostnames would appear in the log and no risk of partial loop?
But before you do so, here's another interesting question to contemplate:
Do you really need your FritzBox router to use Pi-hole as upstream?
Since you also have your FB configured to distribute your Pi-hole as local DNS resolver, having it use Pi-hole as upstream would just result in filtering your guest network also.
Thus, If you do not need or want your guest network to be filtered, you wouldn't need to configure Pi-hole as your router's upstream.
And that because the router tells all the clients in my network (except the clients in my guest network) to use my PiHole via broadcasting anyway. So the clients would use my RPi directly instead of going to my router and then getting the answer where to go for DNS? I am new to networking, sorry for noob level here.
