Retrieval of supported OS list failed "couldn't get address for..."

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1

Hi Again,
I "fixed" the issue by adding 127.0.0.1 to /etc/dhcpcd.conf under static domain_name_servers but never had to do before - how come?
Steen

Hi,
Having a strange issue.
A few weeks back I had same issue "Retrieval of supported OS list failed" when doing the sudo pihole -up on a Raspberry Pi (Model B Plus Rev 1.2) I erased, reinstalled latest OS "Raspbian GNU/Linux 11 (bullseye) V 11.4" and latest version of pihole 5.11.4 = running fine.
I powered down the Pi as I had to travel, but left the other Pi with same OS/pihole version, but a different model (Pi 3 Model B Plus Rev 1.3) running.
When back I powered on the "offending Pi" and I had the same error back.
Full error message is:
*** [ DIAGNOSING ]: Operating system
[i] dig return code: 10
[i] dig response: dig: couldn't get address for 'ns1.pi-hole.net': failure
[✗] Distro: Raspbian
[✗] Error: Raspbian is not a supported distro (Prerequisites - Pi-hole documentation)

Pihole status:
[✓] FTL is listening on port 53
[✓] UDP (IPv4)
[✓] TCP (IPv4)
[✓] UDP (IPv6)
[✓] TCP (IPv6)
[✓] Pi-hole blocking is enabled

Pihole update fails with:
[✗] Retrieval of supported OS list failed. dig failed with return code 10.
Unable to determine if the detected OS (Raspbian 11) is supported

I then did:
sudo PIHOLE_SKIP_OS_CHECK=true pihole -r

Which resulted in:
[✗] Downloading and Installing FTL
Error: URL https://github.com/pi-hole/ftl/releases/latest/download/pihole-FTL-armv6-linux-gnueabihf not found
[✗] FTL Engine not installed

I have generated a debug log , but log couldn't be uploaded:
curl failed, contact Pi-hole support for assistance.
* Error message: curl: (6) Could not resolve host: tricorder.pi-hole.net

Not sure why host couldn't be resolved, perhaps the sudo PIHOLE_SKIP_OS_CHECK=true pihole -r broke something?
Not sure how to upload the error log.

I have looked at the debug log from bot Pis but I see only the issue related to the OS version, there might for sure be other differences I have overlooked.

I can for sure delete all, re-install the OS then pihole, etc, but that don't solve the underlaying issue.

Suggestions?

I am running unbound version 1.13.1.

2

That message shows that your host machine wasn't able to resolve ns1.pi-hole.net.
This in turn prevents Pi-hole's update script to determine whether your OS would match with an entry in Pi-hole's list of supported OSs (your Raspbian 10 would be supported).

To address this, you have to ensure that your host machine running Pi-hole is able to resolve DNS requests.

Note that this is independent from the DNS servers that Pi-hole would be using:
As far as Pi-hole's DNS server is concerned, the host system's DNS configuration is irrelevant for Pi-hole's operation. Pi-hole is using the upstream DNS servers that you've explicitly configured it for.

Your proposed fix of adding 127.0.0.1 would have your host system use Pi-hole for DNS as well.

I'd recommend to also ensure your system is using a reachable public DNS server as upstream DNS resolver.
This would allow your Pi-hole host system to resolve DNS even when Pi-hole should be rendered inoperative for some reason.

3

Hi,
To be sure I fully understand then:
My network is
Internet - ONT - Router - Switch0 - Pihole0
Switch1 - Pihole1
Router have DNS IP Pihole0 and Pihole1
Pihole0 & 1 uses Unbound as Upstream DNS Server

Pihole0 works fine no issue, issue is with Pihole1

Your suggestion is to add an Upstream DNS Server to the Router, will this not defeat the concept of using the Pihole?
In the years using Pihole I have never added a public DNS Server to the Router and I have blocked for the Router to use the ISPs DNS Servers.

Perhaps I have misunderstood you?

4

I did not mention router at all.
I was referring to the DNS resolver that the system that is hosting your Pi-hole is using for DNS.

5

OK, thanks...
It is then fine that I am using 127.0.0.1 in the dhcpcd.conf?

6

I would advice to select another DNS IP other than the own loopback IP 127.0.0.1 for the static domain_name= field in the /etc/dhcpcd.conf file.
If you break Pi-hole for some reason, update/tweak/change, all other processes running on the Pi-hole host will lose DNS resolution making things difficult to diagnose or fix.

I have configured my router IP 10.0.0.1 below but you could also choose to configure your ISP provided DNS servers or public ones like Cloadflare or Quad9:

pi@ph5b:~ $ tail /etc/dhcpcd.conf
[..]
interface eth0
  static ip_address=10.0.0.4/24
  static routers=10.0.0.1
  static domain_name_servers=10.0.0.1

Below ones need to reply with an ANSWER SECTION returning an IP or text for pihole -up to work:

dig ns1.pi-hole.net a

dig ns1.pi-hole.net aaaa

dig @ns1.pi-hole.net versions.pi-hole.net txt

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7

Understood and thanks!

1 Like
8

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