When I first tried working on ICE to Hamburg from my laptop, I couldn’t reach the wifi login page. It was able to connect though so the issue must be somewhere deeper. I’m on Ubuntu 22.04 and here’s how I solved it.

Check the IP

We can check that our device got an IP address assigned by running ip -4 addr. You’ll see something along the lines of:

1: lo: ...
2: wlp0s20f3: ... UP ...
    inet <your-ip-address> brd 172.18.255.255 ...
3: br-2d004261a670: ...
    inet 172.19.0.1/16 ...
4: br-380a59df812e: ...
    inet 172.18.0.1/16 ...
5: docker0: ...
    inet 172.18.0.1/16 ...

The wlp0s20f3 interface has an IP address but the default gateway collides with networks created by the docker daemon.

Change the docker address range

We need to move docker and the created bridges out of the way. This can be done by editing the /etc/docker/daemon.json file. If it’s not there yet, create it with this content:

{
	"bip": "172.26.0.1/16"
}

Try sudo service docker restart afterwards. If the IP address of docker did not change, restart your device and let me know. 😁

Cleanup the old interfaces

You’ve probably noticed that the br-xxxx devices are still there. Let’s remove them with this command:

sudo docker network prune

Open the wifi login page

Go to wifionice.de or bahn.de. It should work now! 🎉