DNS Server Failure

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1

I'm going to apologise if this has already been talked about, but I haven't been able to fix this based on my searches so far.

Getting a DNS server failure in the Pi hole when I log in to the browser interface. No other errors in the browser interface. Updated gravity. Ran the pihole -d command. Running under the assumption that it was a port 53 issue, I tried disabling and stopping dnsmasq, but the response I get is...

unit dnsmasq.service does not exist

  • Operating System : Pi Os
  • Hardware: Raspberry Pi 4

Debug Token:

https://tricorder.pi-hole.net/gYcWGH2J/

2

Your debug log shows that a few days ago (September 29) Pi-hole was starting correctly:

2026-09-29 22:01:07.963 EDT [1448M] INFO: PID of FTL process: 1448
2026-09-29 22:01:08.006 EDT [1448M] INFO: listening on 0.0.0.0 port 53
2026-09-29 22:01:08.006 EDT [1448M] INFO: listening on :: port 53

It also shows that the current issue is really caused by port 53 already in use:

2026-10-02 18:40:47.647 EDT [4964M] INFO: PID of FTL process: 4964
2026-10-02 18:40:47.649 EDT [4964M] CRIT: Error in dnsmasq configuration: failed to create listening socket for port 53: Address in use

But the port diagnostic shows Pi-hole using the UDP port 53 (but no TCP port) and a dnsmasq instance using port 53 for a different IP:

*** [ DIAGNOSING ]: Ports in use
    (...)
[✓] udp:0.0.0.0:53 is in use by pihole-FTL
    (...)
[✗] udp:10.12.194.1:53 is in use by dnsmasq
     (...)
[✗] tcp:10.12.194.1:53 is in use by dnsmasq
    (...)

Try these commands to stop dnsmasq again and restart Pi-hole:

sudo systemctl stop dnsmasq
sudo systemctl disable dnsmasq

sudo systemctl restart pihole-FTL.service
3

Like I said earlier, I tried to run those commands and I get a response that dnsmasq does not exist.

I'm considering just uninstalling pihole and reinstalling it.

4

Uninstalled and reinstalled. Still got the same problem.

Failed to stop dnsmasq.service : unit dnsmasq.service not loaded

Failed to disable unit: unit dnsmasq.service does not exist

5

The debug log shows dnsmasq is running and using port 53.

If there is no dnsmasq service, there is a different service starting it (probably NetworkManager).

6

I would have expected to see something like

dns=dnsmasq

If the network manager was using it, but I'm not seeing it.

Tried to use

sudo systemctl mask dnsmasq

But keep getting the same problem. It says it's not there and the pihole diagnostic gives the same results.

New to Linux and pihole so please excuse my ignorance here.

7

Please post the output of sudo ss -tupnl '( sport = 53 )'.

8

Plus a couple more?

pstree -ps $(pidof -s dnsmasq)

apt policy dnsmasq-base

apt --installed rdepends dnsmasq-base

9

ared@RaspberryPi:~ $ sudo ss -tupnl '( sport = 53 )'
[/quote]

^[[201~Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
udp UNCONN 0 0 0.0.0.0:53 0.0.0.0:* users:(("pihole-FTL",pid=1811,fd=21))
udp UNCONN 0 0 10.12.194.1:53 0.0.0.0:* users:(("dnsmasq",pid=1468,fd=6))
tcp LISTEN 0 32 10.12.194.1:53 0.0.0.0:* users:(("dnsmasq",pid=1468,fd=7))

10

sudo pstree -ps $(pidof -s dnsmasq)
systemd(1)───NetworkManager(748)───dnsmasq(1468)

11

sudo apt --installed rdepends dnsmasq-base
dnsmasq-base
Reverse Depends:
Recommends: network-manager
dnsmasq-base:armhf
dnsmasq-base:armhf
dnsmasq-base-lua:armhf
dnsmasq-base-lua
Replaces: dnsmasq-base
dnsmasq-base:armhf
dnsmasq-base:armhf
dnsmasq-base-lua:armhf
dnsmasq-base-lua
Recommends: network-manager
dnsmasq-base:armhf
dnsmasq-base:armhf
dnsmasq-base-lua:armhf
dnsmasq-base-lua
Replaces: dnsmasq-base
dnsmasq-base:armhf
dnsmasq-base:armhf
dnsmasq-base-lua:armhf
dnsmasq-base-lua

12

apt policy dnsmasq-base
dnsmasq-base:
Installed: 2.91-1+deb13u2
Candidate: 2.91-1+deb13u2
Version table:
*** 2.91-1+deb13u2 500
500 http://deb.debian.org/debian trixie/main arm64 Packages
100 /var/lib/dpkg/status
2.91-1+deb13u1 500
500 http://deb.debian.org/debian-security trixie-security/main arm64 Pa>
lines 1-9/9 (END)

13

Grep for it:

sudo rgrep dns= /etc/NetworkManager/