26 Sep 2024

Reconcile Docker With Deutsche Bahn

If WiFi does not work on Deutsche Bahn's ICE trains and you have Docker installed, there may be network interference which can be fixed easily.

Daniel Kraus

networkDeutsche BahnDockertravel

2024-09-26 09:07 +0000

Composition of screenshots

If you happen to be a (Linux) power user travelling on a Deutsche Bahn ICE long-distance train and you wonder why you don’t get a working network connection with the complemenatary “WIFIonICE” wireless network, there may be a network interference on your laptop.

There are multiple solutions for this on the web. My favorite solution is to change Docker’s network configuration by editing (or creating) the file /etc/docker/daemons.json. However, you may need to prune existing Docker networks first. Otherwise the Docker service will fail to start with the following message:

failed to start daemon: Error initializing network controller: error creating default "bridge" network: all predefined address pools have been fully subnetted

Therefore, I recommend the following steps (this is on a Fedora Linux system with systemd):

  1. Stop any docker containers that you may have running, including services managed by docker compose.

  2. Prune the networks:

    docker network prune

  3. Create or edit /etc/docker/daemon.json so that it contains the following:

    {
    "default-address-pools":
    [
        {"base":"172.19.0.0/16","size":24}
    ]
}

  4. Restart docker:

    systemctl restart docker

  5. Connect to WIFIonICE and enjoy your network connection :-)

References