Bug in DNS CNAME handling of home assistant OS?!

hi all, i might have found a bug in dns resolution in hass.io. i had a separate pihole instance in my network, which i moved into a docker container on a linux host. after moving pihole from a host into a container the integration stopped working.

setup before:

  • pihole host:
  • pihole dns: “pihole.my.domain → A”
  • integration working
  • browser access working

setup after:

  • pihole host: (generic linux vm with multiple containers)
  • pihole dns: “pihole.my.domain → CNAME box.my.domain”
  • integration stopped working
  • browser access still working

when i connected into the hass vm using ssh i got this (really weird) behavior:

$ curl pihole.my.domain
curl: (6) Could not resolve host: pihole.my.domain
$ host pihole.my.domain
pihole.my.domain is an alias for box.my.domain


  • pihole dns: "pihole → A`
  • integration working again
  • browser access still working
  • curl in SSH session working again as expected

it seems hass does not resolve CNAMEs correctly, which is basically just astonishing cause i would not even know how to achieve this if i wanted to (to not “just handle” CNAME responses correctly). can somebody maybe confirm this behavior?

Home Assistant OS.

Not hass.io

duly noted.

Heh I’ve just been banging my head against the wall with this same issue for the last 4 hours too.

I had:

domain -> domain2
domain2 -> domain3
domain3 -> IP

As soon as I changed it to:

domain -> IP

it then worked