I am running Pi-Hole v5.8 - FTL v5.13 - Web Interface v5.10 on a virtual machine as a recursive DNS for my Linux box.
Recently I found that DNS setting I put in my ADSL modem pointing to the VM running pi-hole had been changed.
I noticed it only because I logged into pi-hole and noticed that the upstream server graph looked different.
So I logged into the modem, saw the DNA setting had been changed to point to an external DNS server and changed it back to mine, 192.168.1.5.
No big deal but it should not have happened.
Maybe because of a reset I did not notice, a power cut while I was away from home?
In any case, I was looking to see if there was some indicator of the DNS being used in the pi-hole Dashboard so I could easily check it at a glance but have not found it.
Like in the 'Status' list, where it lists these items:
Active
Load: 0 0 0
Memory usage: 3.6 %
No temp sensor found
Can it be set to also list the DNS server being used?
... but in the web GUI, within the 'Status' list instead of having to SSH into the VM and typing into the terminal.
eg:
Status
Active
dns-server: 192.168.1.5
Load: 0 0 0
Memory usage: 3.7 %
No temp sensor found
Seeing this tidbit of information at a glance seems useful to me as it would let me know if pi-hole was or was not using the recursive DNS I had set up.
Like in the case I wrote about in my OP.
Maybe it could be done without great effort.
Some config setting?
There is no single truth here.
Your router may not support configuring local DNS servers at all, but as long as you are able to configure Pi-hole as your router's upstream, that would still be a viable configuration. And there may be more than one DHCP server in your network. And any client may be configured to override DHCP provided DNS servers, either by your or by its OS's or even some specific software maker's intention.
(And note that Pi-hole is not a recursive resolver - it is a filtering DNS forwarder).
... but as long as you are able to configure Pi-hole as your router's upstream ...
That is what I am doing, in the LAN Setup page of my router's admin UI:
DNS Server 1: 192.168.1.5
DNS Server 2: 192.168.1.5
All I would want to be able to do is to see that IP address under the 'Status' list.
If that is possible without much ado, it would be great.
ie: some config setting for the 'Status' list.
There may be some confusion here. If you are using a recursive upstream DNS server for Pi-hole (e.g. unbound), this is invisible to the router and the DHCP service. The clients would be using Pi-hole for DNS, and Pi-hole in turn is using unbound to resolve domain names that are not blocked by Pi-hole. The clients have no visibility into the upstream DNS server used by Pi-hole.
You can verify that Pi-hole is using unbound by looking at the Upstream Servers pie chart on the dashboard. The local unbound instance will be shown on the loopback IP at the port you assigned - our guide uses 5335.
Pi-hole is using unbound as the upstream DNS server. This is separate from any router settings.
Ah ...
So, when I set my router to use the VMs IP address (192.168.1.5) what I am doing is setting it to use unbound (which runs in the VM) as the DNS server.
Not exactly. You are setting the DNS server to Pi-hole, which in turn is using unbound for upstream DNS resolution. The router does not see or know of the presence of unbound.
... setting the DNS server to Pi-hole ...
... router does not see or know of the presence of unbound.
I see.
So when (for whatever reason) the router resets the DNS1/DNS2 server settings to what is probably the default setting for my ADSL provider, pi-hole loses the recursive part. Correct?
Not correct. The link between Pi-hole and the upstream recursive DNS server (unbound in your case) is within the Pi itself and completely independent of any router settings.
Your upstream DNS server is defined on the loopback IP for the Pi (127.0.0.1) and the specified port (5335 per our guide). That link stays intact regardless of anything the router may be changing.
