Expected Behaviour:
DNS resolution should be consistent and work every time.
I have two PiHoles running and they both have the same issue:
- Linux PIHOLE01 5.15.84-v7l+ #1613 SMP Thu Jan 5 12:01:26 GMT 2023 armv7l GNU/Linux on Raspberry Pi B+
- Linux PIHOLE02 5.15.84-v7l+ #1613 SMP Thu Jan 5 12:01:26 GMT 2023 armv7l GNU/Linux on Raspberry Pi B+
Actual Behaviour:
PiHole is randomly not able to resolve DNS queries. When I try to do a gravity update or pinhole update, for example, I will get errors related to not being able to resolve a domain (that exists) or I will see this error:
[✗] DNS resolution is currently unavailable
It will wait and try again and everything works just fine.
I had tried changing the PiHole DNS Servers from Level3 to Google with no luck.
My clients are all having random issues with dns resolution as well. I will issue an nslookup from a client and it will timeout and then immediately reissue it and it will work.
This seems to have just started in the past two or three days with no other network changes.
Debug Token:
PIHOLE01: https://tricorder.pi-hole.net/CL5WIoXk/
PIHOLE02: https://tricorder.pi-hole.net/k1A9ftyX/
Example of the issue from PiHole01:
[✓] ** FINISHED DEBUGGING! **
* The debug log can be uploaded to tricorder.pi-hole.net for sharing with developers only.
[i] Debug script running in automated mode
* Using curl for transmission.
* curl failed, contact Pi-hole support for assistance.
* Error message: curl: (6) Could not resolve host: tricorder.pi-hole.net
[✗] There was an error uploading your debug log.
* Please try again or contact the Pi-hole team for assistance.
* A local copy of the debug log can be found at: /var/log/pihole/pihole_debug.log
pi@PIHOLE01:~ $ nslookup tricorder.pi-hole.net
Server: 127.0.0.1
Address: 127.0.0.1#53
Non-authoritative answer:
tricorder.pi-hole.net canonical name = docker-2-ny1.pi-hole.net.
Name: docker-2-ny1.pi-hole.net
Address: 164.90.255.4
pi@PIHOLE01:~ $
At the same time this happened on PiHole02:
pi@PIHOLE02:~ $ nslookup tricorder.pi-hole.net
;; connection timed out; no servers could be reached
pi@PIHOLE02:~ $
I did a PCAP from my router/firewall and see this for the traffic from PIHOLE01: