Deutsche Bahn,Docker and Wifi in an ICE and VPN problems

The Deutsche Bahn is providing free wifi for some years now. It works for most of the people pretty well, but if you are a developer you could have some issues. I was suffering a lot with this, this is why I’m posting it, to help some of you

As you can see, the WiFi is running on the IP


If you are running docker it can happen, that you have in your ifconfig a bridge already on this IP:

$ ifconig

br-bcc4b1218247: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet netmask broadcast
ether 02:42:55:fb:67:74 txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

you can delete this bridge by using the following commands:

sudo ip link set br-bcc4b1218247 down
sudo brctl delbr br-bcc4b1218247

This should work, that you can connect then to the WiFi on Ice

UPDATE: 12.09.2023

Loginpage is not opening

Normally the login page should update automatically, but soemtimes (on Linux) it isn’t.
Go to for opening it in your browser

UPDATE: you can also delete all docker networks easily with:

$ docker network prune

I had the problem, that I could not reach some websitse in our company network,when I’m using a VPN. The ping to our internal subdomain was working, but I could not reach it in my browser:

$ ping
PING (10.x.x.x) 56(84) bytes of data.
64 bytes from 10.x.x.x (10.x.x.x): icmp_seq=1 ttl=254 time=108 ms
64 bytes from 10.x.x.x (10.x.x.x): icmp_seq=2 ttl=254 time=192 ms
64 bytes from 10.x.x.x (10.x.x.x): icmp_seq=3 ttl=254 time=697 ms
64 bytes from 10.x.x.x (10.x.x.x): icmp_seq=4 ttl=254 time=344 ms
64 bytes from 10.x.x.x (10.x.x.x): icmp_seq=5 ttl=254 time=52.2 ms
64 bytes from 10.x.x.x (10.x.x.x): icmp_seq=6 ttl=254 time=54.3 ms
64 bytes from 10.x.x.x (10.x.x.x): icmp_seq=7 ttl=254 time=267 ms
64 bytes from 10.x.x.x (10.x.x.x): icmp_seq=8 ttl=254 time=181 ms
64 bytes from 10.x.x.x (10.x.x.x): icmp_seq=9 ttl=254 time=141 ms
--- ping statistics ---
9 packets transmitted, 9 received, 0% packet loss, time 13011ms

the ifconfig for the vpn tunnel and the wifi were showing the following:

wlp4s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1440

My colleague, who is traveling every day by the ICE of Deutsche Bahn told me to set down the MTU, then everything was working: