I have a sudden issue, which was just there, without my direct action.
I have PiHole with unbound as my internal DNS server and as it seems it just stops DNS resolving. But the strangest thing is, that this website here works. Also another forum works. But the most sites get no connection. I thought it was overblocking, but it’s not the case. I disabled the blocking for some seconds, but the issue stays. If I want to upgrade gravity, I get: DNS resolution is currently unavailable.
I tried also to set another DNS server within PiHole (22.214.171.124 just to be sure), but the issue stays also.
Jul 07 09:52:56 nextcloud systemd: Starting unbound.service - Unbound DNS server...
Jul 07 09:52:56 nextcloud unbound: [1146:0] warning: subnetcache: serve-expired is set but not working for data originating from the subnet module cache.
Jul 07 09:52:56 nextcloud unbound: [1146:0] warning: subnetcache: prefetch is set but not working for data originating from the subnet module cache.
Jul 07 09:52:56 nextcloud unbound: [1146:0] info: start of service (unbound 1.17.1).
Jul 07 09:52:56 nextcloud systemd: Started unbound.service - Unbound DNS server.
or, that may be the point (just wondering why the problem comes now and all the time before everything was working). I get the old IP of another pihole, I used before (because of the switch of devices).
But what should I have there? Should the settings in resolv.conf be the same as in 'Settings → DNS → upstream DNS server? I suppose no, if I use unbound. But where do I change the DNS server for the pihole itself? Directly in resolv.conf or are there any web GUI settings for that?
The Pihole device uses what is inside /etc/resolv.conf, but the clients which connect to pihole use the DNS you set in the pihole webinterface.
Best practice is to set the pihole device to an external DNS service, in case pihole fails you have still internet on the pihole device itself.
If the DNS in resolv.conf points to an non-existing IP than nothing can be resolved. You can change the line inside the file or use dietpi-config and at the network settings you can change the DNS server.
I changed it in resolv.conf and now I can update gravity, so the pihole gets access to the internet.
BUT I still get no internet for the clients. I changed the DNS server (in the GUI) again from unbound to 126.96.36.199, but it still doesn’t work.