not able to use "host.docker.internal"

[iscu2020]

Hello,
I'm using Rancher Desktop Version: 1.18.2 with Ubuntu and wsl2:

>wsl -l -v
  NAME                    STATE           VERSION
* Ubuntu                  Running         2
  rancher-desktop         Running         2
  rancher-desktop-data    Stopped         2

Ubuntu is visible and checked in the WSL integrations:

Unfortunately I cannot use host.docker.internal, neither from inside Ubuntu, nor from any container started from there:

$ping host.docker.internal
ping: host.docker.internal: Name or service not known

From inside the container the same story:

bash-4.4$ echo "test" > /dev/tcp/host.docker.internal/1521
bash: host.docker.internal: Name or service not known
bash: /dev/tcp/host.docker.internal/1521: Invalid argument
bash-4.4$ echo "test" > /dev/tcp/172.17.0.1/1521
bash-4.4$

As you can see above, when using the ip of the gateway, it works..

Any advice would be greatly appreciated, thank you !

[iscu2020]

Ok, I found out in docker.log file this repeating message:

unable to configure the Docker daemon with file /etc/docker/daemon.json: the following directives are specified both as a flag and in the configuration file: hosts: (from flag: [unix:///mnt/wsl/rancher-desktop/run/docker.sock unix:///var/run/docker.sock], from file: [tcp://0.0.0.0:2375 unix:///var/run/docker.sock])

I see that this subject appeared in the past here: #2304 and that the ticket is still Open: #2851

My /etc/docker/daemon.json indeed contained tcp://0.0.0.0:2375 (mainly for test-containers).
I removed the file completely from my Ubuntu distro and restarted.. but still I see the same error.

Is that file cached somewhere else? Or how can I make it go away?

[iscu2020]

Me again, answering my own questions :)

I found the /etc/docker/daemon.json file in rancher desktop (used rdctl shell to access it). I removed it from there and restarted.

Now I don't see those errors anymore, but I'm still blocked as host.docker.internal is still not available.

Could anybody give me some directions on how to debug this, please?

[iscu2020]

I found out why it wasn't working.. I had a docker service configured by myself on Ubuntu. Probably this is why rancher couldn't start it's own docker env on my Ubuntu installation.
As soon as I removed it, I had access to host.docker.internal