Web Interface is not working (Unable to Connect)

[Luca_Gandolfo]

The issue I am facing:
I would like to access the web interface, but when I type the address into my browser, it shows 'Unable to connect' (for both Firefox and Chromium)
I'm new to this, so I believe it's my fault for not recognizing the issue.
Details about my system:
Machine: Dell FX170
OS: Debian GNU/Linux 12 (bookworm) i686
Kernel: 6.1.0-13-686-pae
Router: TIM HUB+ (ZTE H388X)
Debug token:
https://tricorder.pi-hole.net/ddUbnGhK/

[chrislph]

Your web server is running on port 81. The address to use here is

http://pi.hole:81

or

http://192.168.1.50:81/admin

[Luca_Gandolfo]

Thank you so much but It only works the second link
The first one it's "Unable to connect again"

[chrislph]

What is the output of the command

nslookup pi.hole

[Luca_Gandolfo]

gandalf@Pi-Hole-Gandalf:~$ nslookup pi.hole
Server:	192.168.1.1
Address:	192.168.1.1#53

** server can't find pi.hole: NXDOMAIN

[chrislph]

Thanks. Your router at 192.168.1.1 is the DHCP server and is telling clients to use itself (the router) for DNS

   * Received 317 bytes from enp1s0:192.168.1.1
     DHCP options:
      router: 192.168.1.1
      dns-server: 192.168.1.1

To fix this, go into your router settings and find the LAN / DHCP section. There should be a DNS section in there which will be blank or set to the router. Change it to be your Pi-hole which is at 192.168.1.50. Save the changes.

Then take your Dell off and back on to the network (eg unplug and replug cable or toggle wifi off and on) so it picks up the new settings.

Finally, try the nslookup command again on the Dell and it should work. If so, try the first http link and that should be working now too and you will be using Pi-hole and seeing queries appearing in its Query Log.

[Luca_Gandolfo]

This is the section for DHCP server on my router.
Whitch parameter I should modify?

[chrislph]

Those are all the settings for the IP address range and lease time. Is there any section for DHCP DNS, maybe another tab or Advanced section or something like that?

It might be that this router defaults to using itself for DNS and there is no way to change this.

As a temporary measure you can set the DNS of your Dell manually to use the Pi-hole. If you have a desktop on your Dell, open the wired or wireless settings (depending on which you are using to connect), usually an icon in the toolbar. You should be able to edit the IPv4 settings in there and override the DNS setting to change the router IP to the Pi-hole IP.

That will mean your Dell can access the web interface by that first pi.hole link and will be using it for DNS. Other devices on your network though will continue to be using the router for DNS until the router setting is changed, if that is possible.

There are other approaches available too – you can tell the router to use your Pi-hole for its DNS, and it will be working, but everything in the Pi-hole will appear to come from the router. Or you can disable the router's DHCP and turn on the Pi-hole's DHCP and use that instead. However the screenshot you posted shows mobile settings and I would be worried about breaking those with either of these two approaches, if the router even supports them.

[Luca_Gandolfo]

I search through the internet and I found that my router does not provide any modification of the DNS.
I've already order a new one (a TP-Link Archer AX55)
When it arrive i'm going to test it.
Thanks in advance for your help.
I need to mark as solved?