Pi.hole cannot be found


#1

Expected Behaviour:

I’d expect my systems to route traffic through the pi-hole and be able to access the admin interface through “pi.hole”.

Actual Behaviour:

However, I can’t access pi.hole. I can access the dashboard via the Raspberry Pi’s IP. Ads do not get blocked.

Debug Token:

https://tricorder.pi-hole.net/zlwr250mif

For my setup:

  1. Installed a new raspbian today
  2. Installed pi-hole today
  3. Configured my router to route DNS through the pi-hole. The pi has a static ip (192.168.11.6) which is configured as the only DNS server in my router (192.168.11.1), see figure below.

Initially I had the impression the pi-hole was working. The dashboard showed me a lot of queries and also blocks. But after a reboot (I relocated the hardware to its designated spot) I encounter the problems.

The nslookup also shows an error:

~> nslookup pi.hole 192.168.11.6
Server:		192.168.11.6
Address:	192.168.11.6#53

Name:	pi.hole
Address: 192.168.11.6

 ~> nslookup pi.hole
Server:		192.168.11.1
Address:	192.168.11.1#53

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

I have the gut feeling this is connected to my router settings but I can’t pin it yet.
Reading


Section 1. -> Caveats -> 2. : Is it even possible to reach pi.hole this way? If I understand that post correct, I will not be able to reach the pi-hole without accessing the ip directly.


#2

Works after another restart of all involved systems. Can’t tell why.


#3

A couple of day later the problem returned. This time it was not solved by a restart of the involved systems.
I can access the dashboard via the pi’s IP but not via pi.hole and again the nslookup throws errors and I see ads.


#4

If 192.168.11.6 responds with a proper IP for pi.hole then Pi-hole is configured correctly. Not having experience with that particular router I wouldn’t know what settings are needed to have it’s internal DNS correctly forward queries to the Pi-hole.

When the problem is happening are there any queries shown in the admin panel query log? Can you run pihole -d and provide us with the token link so that we can check some basic configuration settings for correctness?


#5

Also check if your router DHCP service dishes out the correct details to its clients using the nmap tool on Pi-hole:


#6

nmap dhcp-discover result:

sudo nmap -sU -p67 --script dhcp-discover 192.168.11.1

Starting Nmap 7.40 ( https://nmap.org ) at 2019-03-18 08:55 GMT
Nmap scan report for 192.168.11.1
Host is up (-0.19s latency).
PORT   STATE         SERVICE
67/udp open|filtered dhcps
MAC Address: XX:24:XX:BC:39:XX (Buffalo.inc)

Nmap done: 1 IP address (1 host up) scanned in 12.47 seconds

Debug token

There are queries showing in the admin panel query log.


#7

I am not sure why nmap isnt able to capture DHCP from your router.
Could be some safety mechanism on the router.
If others dont provide a solution, my advice would be to disable the DHCP service on the router and enable it on Pi-hole:


#8

Well then I’ll probably have to

  • either set the pi manually as my DNS server on each device
  • wait for a new router
  • find out why it worked for one day

I can’t disable DHCP in the router :confused:
Thanks nevertheless for your efforts!


#9

image


#10

If you cannot disable DHCP on the router, then change the range of DHCP on the router to one IP address, the IP of the Pi-Hole. Then enable DHCP on the Pi-Hole and assign the range outside the IP of the Pi-Hole.


#11

:roll_eyes: whoops. Thanks!


#12

So, after a bit more trial and error I figured a way out to get it working again:

  1. The pi-hole has to be up & running
  2. The router has to be restarted

(in this order!)

It seems as if the the router is up while the pi-hole goes down it relies on a backup DNS that I cannot see or configure via the interface. If the pi-hole gets back up it does not switch to it as DNS server (even if I update the setting for the DNS server IP address). However, restarting the router does the job.
Thanks for all your help so far!