Suddenly losing DNS

Configuration
1

I don’t know if it was an update, a shutdown or just unluck. But since some day my logs are full of DNS errors, like

Access to https://....met.no/weatherapi/locationforecast/2.0/complete returned error 'ClientConnectorDNSError'
...
aiodns.error.DNSError: (11, 'Could not contact DNS servers')
...
Error requesting homeassistant_alerts data: Cannot connect to host alerts.home-assistant.io:443 ssl:default [Timeout while contacting DNS servers]

etc.
And obviously a lot of integrations (e.g. Matter) won’t work anymore.

Tried manually editing /etc/resolv.conf but it will be automatically overwritten.

Version: core-2026.7.3
Installation type: Home Assistant OS (v. 18.2)
on a raspberry pi 3

How can I fix this?
tnx

3

In Settings → System → Network the network is statically defined. I tried to ping the configured gateway and the ping succeeded.

# [core-ssh ~]$ ha network info                                                                                                                        
docker:                                                                                                                                              
  address: 172.30.32.0/23                                                                                                                            
  dns: 172.30.32.3 # <-- ??? btw ping OK
  gateway: 172.30.32.1
  interface: hassio
  [...]
interfaces:
[...]
- connected: true
  enabled: true
  ipv4:
    [...]
    nameservers:
    - 208.67.222.222 # opendns
    - 208.67.220.220 # ping OK
    [...]

I turned off ipv6 but it didn’t help

#[core-ssh ~]$  ha dns info
fallback: true
host: 172.30.32.3
llmnr: true
locals:
- dns://208.67.220.220 # opendns
- dns://208.67.222.222
mdns: true
servers: []
update_available: false
version: 2026.08.0
version_latest: 2026.080

# [core-ssh ~]$ ping en.wikipedia.org
ping: bad address 'en.wikipedia.org'
# [core-ssh ~]$ ping 185.15.58.224 # (en.wikipedia.org's IP)
PING 185.15.58.224 (185.15.58.224): 56 data bytes
64 bytes from 185.15.58.224: seq=0 ttl=49 time=72.175 ms
4

First just so you know Pi3 aren’t supported on current builds anymore. HA requirements have exceeded 1 gb ram and the pi 3 can’t satisfy the minimum. It may have… Weirdness. The smallest pi they support is the 2g pi 4

So. That resource constraints issue above isn’t too far fetched.

That said… Does it persist through a restart?

5

yes, I’ve restarted the Pi many times

6

You could use the “back to basic” approach

Set your dns to your local-lan-address ( usually same as IP of your gateway )

This way your leave up to your Router and ISP to deal with DNS requests, and leave fallback as true
( But make sure you dont have typed in dns anywhere else, as HA has it’s own “fallback address” by default ( If you don’t overwrite this )

I don’t know your initial reasons to add those 2 nameservers ( if you actually also really don’t know, the better the reason to use the basic setup )

So your local gateway IP, under ipv4 nameservers, and in specific under " locals ":

7

Uh I found that in the settings → system → logs there are the logs of the DNS container and are full of messages

homeassistant hassio_dns\[600\]: s6-supervise coredns: warning: unable to spawn ./run (waiting 60 seconds): Exec format error

[EDIT] network configuration was working untouched for months

8

Ditch Your PI3

9

top load averages are about ~0.38-0.40, don’t seems excessive (one third of core used over 4 available).
RAM usage is higher, about 70%. But would hassio_dns eat 200MB+ memory?

10

Well my commend above was just kind of a joke, as i suggested you to try to “revert” to basic settings for DNS in HA, and your answer only contain log warning/error, and no response to whether how default-settings “behave”
My bad, but it kind of indicates , that i have no further thoughts or recommendations to “add”

PS: if i.e DNS errors out, alot of “transactions” is “pilling up” waiting for response (that could be what “eating” up your ram ) Not the DNS-Requests

NOTE: " Locals: " Do You know what this means ? , This indicates to me, that you really don’t know why you have manually changed Your DNS settings, and therefore You should just use defaults