DNS not working

Help
1

Expected Behaviour:

  • Operating System: Ubuntu 24.04.4 LTS
  • Hardware: Dell Optiplex7040. i5-6500. 8Gb

Actual Behaviour:

I had pihole running successfully for a couple of year on a Dell thin client. A hardware failure meant that I purchased another Dell thin client and have set up a fresh install of both Ubuntu and Pi-hole.

Pi-hole has installed successfully. The Ubuntu machine has a static IP 192.168.1.169 on my LAN. DHCP is on the LAN router (AX53).

I have set the upstream DNS setting in Pi-hole to Google .

In my router configuration if I change the primary DNS to my Pi-hole static IP (192.168.1.169) then I lose all Internet connectivity on the Pi-hole server and the clients. If I change the primary DNS to 8.8.8.8 and secondary to 8.8.4.4 then connectivity is restored.

I've been going round in circles with this one. Bear in mind I am a complete dummy when it comes to Ubuntu and Linux, so whilst I am super grateful for any help you will have to parse such help as if you are speaking to a very slow Labrador dog....

Why am I losing connectivity when I tell me router to use the Pi-hole for DNS?

Debug Token:

https://tricorder.pi-hole.net/GBAqWrAl

2

Where are you changing this?

On the WAN/Internet settings? Or on the DHCP/LAN/Network settings?

3

In the Advanced>Network>Internet section of the router configuration (currently set to the Google DNS servers)

Screenshot 2026-04-30 194523
Screenshot 2026-04-30 194523941×852 68.1 KB

4

If your router interface is similar to the one on the online emulator, you should try to change the DNS setting on the "DHCP server" page:

image
image1144×401 20 KB

The DNS server on the "Internet" page can be set to the default values, or any other public servers, like 8.8.8.8.

5

OK. I will try that.

The Internet configuration page needs to have an address in the Primary DNS field. Do I leave at 8.8.8.8 (or other DNS provider)?

6

Yes.

  • Select the "Use the Following DNS Addresses" and type any public DNS server you like

or

  • use the "Get Dynamically from ISP" and use the servers provided by your ISP.
7

Brilliant!

Thanks for the help......told you that i was crap at this stuff!