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Enable TCP port 2375 for external connection to Docker

Enable TCP port 2375 for external connection to Docker

See this issue.
Docker best practise to Control and configure Docker with systemd.

  1. Create daemon.json file in /etc/docker:

     {"hosts": ["tcp://", "unix:///var/run/docker.sock"]}
  2. Add /etc/systemd/system/docker.service.d/override.conf

  3. Reload the systemd daemon:

     systemctl daemon-reload
  4. Restart docker:

     systemctl restart docker.service
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webzakimbo commented Sep 28, 2022

Here's another way that worked for me:


 ExecStart=/usr/bin/dockerd --config-file /etc/docker/daemon.json


  "hosts": ["tcp://", "unix:///var/run/docker.sock"]

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Thanks! for me it required a reboot to work

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AbdelazizSharaf001 commented Dec 9, 2022

AFAIK, Docker will be run as daemon wherever you deploy it.

Docker in Docker has two versions

  • docker:latest daemond and host dependant
  • docker:dind web interface based (seems to be no daemon | or fully isolated from host)

I was testing docker, minikube, and K8s functionalities inside docker

The way I was able to do that without exec command is docker context

for me it was not a server or daemon problem, but a context one

This answer helped me connecting to remote docker client and docker in docker via contexts :

So now we have both exposing docker via tcp and connecting to docker via tcp in this thread..

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AbdelazizSharaf001 commented Dec 9, 2022

Another thing to think for is security

Is the exposed port with your methods are encrypted or not ?

docker:dind has two ports to expose

  • 2375 no encrypton - context do not require cert or key
  • 2376 encrypted - context require key pair to qualify connection

Is that encryption applicable with your methods ?

I think this is the part where we go inside docker:dind entry point file

so it should be this part

dockerd \
     --host="$dockerSocket" \
     --host=tcp:// \
     --tlsverify \
     --tlscacert "$DOCKER_TLS_CERTDIR/server/ca.pem" \
     --tlscert "$DOCKER_TLS_CERTDIR/server/cert.pem" \
     --tlskey "$DOCKER_TLS_CERTDIR/server/key.pem"

and @russellhoff : you are right

  • the daemon server is running but as an entrypoint and not a service (I miss understood)

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abel-delafuente commented Dec 29, 2022

When i try to build the image be means of the BuildImage command, i am getting the

Connect to [/] failed: Connection refused: no further information

Apparently Gradle does not make match with the WSL platform IP.

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thanks a lot

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KMMehr commented Jan 14, 2023

Great job

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@abel-delafuente tcp not http
you could also try to use a unix socket instead and test again to make sure if it's a docker behavior or a network restriction

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Great! It's working for me.

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