Reconcile Docker with Deutsche Bahn.

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daniel 2024-09-26 12:03:54 +02:00
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---
title: "Reconcile Docker With Deutsche Bahn"
description: >
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.
date: 2024-09-26T09:07:30Z
draft: false
# ShowLastmod: true
toc: false
scrolltotop: true
#featuredImg: reconcile-docker-with-deutsche-bahn.png
tags:
- network
- Deutsche Bahn
- Docker
- travel
---
![Composition of screenshots](reconcile-docker-with-deutsche-bahn.png)
If you happen to be a (Linux) power user travelling on a Deutsche Bahn [ICE
long-distance train][ice] and you wonder why you don't get a working network
connection with the complimenatary "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:
```plain
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:
```bash
docker network prune
```
3. Create or edit `/etc/docker/daemon.json` so that it contains the following:
```plain
{
"default-address-pools":
[
{"base":"172.19.0.0/16","size":24}
]
}
```
4. Restart docker:
```bash
systemctl restart docker
```
5. Connect to `WIFIonICE` and enjoy your network connection :-)
## References
- StackExchange answer that provides the solution as presented here -- see also
the answer about pruning the networks below.
<https://unix.stackexchange.com/a/539258/110635>
- If you don't want to or cannot configure your Docker networks, you can also
turn Docker off and on again when you travel:
<https://kuttler.eu/code/ice-wlan-linux-docker/>
This is what I used to do myself, but nowadays I prefer to just configure the
Docker network differently.
- There are many more internet sources (and I have just added another one...), I
won't copy all those links into my post, see DuckDuckGo search results
for yourself:
<https://duckduckgo.com/?q=docker+wifi+on+ice>
[ice]: https://int.bahn.de/en/trains/long-distance-trains

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