Automatic negotiation of a captive portal: connect to icomera wifi in CD trains without having to jump through hoops.

CDWiFi (České dráhy) WiFi Internet Access

# I believe this is the necessary and sufficient step to get internet access on board the Czech long distance trains (e.g. EuroCity which runs from Prague to Kiel)
curl -vLA '' 'http://cdwifi.cz/portal/api/vehicle/gateway/user/authenticate'

# It says "500 internal server error" but that doesn't keep it from working.

# check with this request, answer should contain "authenticated":1
curl -vLA '' 'http://cdwifi.cz/portal/api/vehicle/gateway/user'

# Also nice: GPS data (but seems outdated)
curl -vLA '' 'http://cdwifi.cz/portal/internal/api/x6/position'

# Really nice: show connectivity including the LTE uplinks
curl -vLA '' http://www.info.cdwifi.cz/api/jsonp/connectivity

Nice, thanks for sharing 👍

You're welcome. I hope it was useful :-)

Im currently in a CD Train, trying to get GPS data :(

Let me know if you get it ;-)
IIRC I found the API link in one of the response HTMLs, maybe there's more interesting stuff in there

and have a safe trip

Thanks :)
so what i found: http://cdwifi.cz/portal/api/vehicle/realtime

Response:

gpsLat":51.476318,"gpsLng":13.52959,"speed":151,"delay":null,"altitude":92.9,"temperature":null

it's a really nice thing to do when you are bored :D

nice, thanks!

oh and there are newer trains like the EC 183, they dont have an "Portal", also WiFi only work in Czech.
GET Request to the Gateway will return an Lorum Impsum Agree Page. Just for anyone that is wondering ^^

Also the data limit outside of CZ is (as often) based in the mac address. So to reset it, just change the mac address of your network interface and reconnect.

macOS:

sudo ifconfig en0 ether <new-mac-address>

Good point.

Nice figuring out of the other hidden services. If you need just a one-click confirmation from command line that work on both Mac and Linux, I've prepared as script: https://gist.github.com/bzamecnik/46bd84c530e61a706ddca8a19263e2c1. It can work around the problem when a custom DNS (such as 8.8.8.8) can't resolve their inner domain. Just install and type cdwifi. :)

@bzamecnik Nice to see that my solution still works. I've linked to yours in the https://github.com/fnordomat/misc/blob/master/captive-be-gone/minisurvey.txt and hope to expand this even further, especially as travel picks up again :-)

thanks

Some more fun: Using the /connectivity/ endpoint, we can see the currently connected links. A command line shortcut to see those that are connected and their signal level:

curl -s  http://www.info.cdwifi.cz/api/jsonp/connectivity/ \
    | tr -d '(' | tr -d ')' | tr -d ';' |  \
    jq '.links[] | select(.link_state=="available")'

{
  "index": "104",
  "device_type": "modem",
  "device_subtype": "sierra-7710",
  "device_state": "up",
  "link_state": "available",
  "rssi": "-55",
  "technology": "lte",
  "operator_id": "26201",
  "apninfo": "railnet.telekom,-1,-1",
  "umts_info": {
    "net_status": "1",
    "lac": "FFFE",
    "cellid": "0231E502"
  }
}
{
  "index": "105",
  "device_type": "modem",
  "device_subtype": "sierra-7710",
  "device_state": "up",
  "link_state": "available",
  "rssi": "-81",
  "technology": "lte",
  "operator_id": "26202",
  "apninfo": "fv1.deutschebahn.com,-1,-1",
  "umts_info": {
    "net_status": "1",
    "lac": "FFFE",
    "cellid": "002AE302"
  }
}

or show only some fields using

curl -s  http://www.info.cdwifi.cz/api/jsonp/connectivity/ \
    | tr -d '(' | tr -d ')' | tr -d ';' |  \
    jq '.links[] | select(.link_state=="available") | {rssi, apninfo, technology}''

{
  "rssi": "-51",
  "apninfo": "railnet.telekom,-1,-1",
  "technology": "lte"
}
{
  "rssi": "-70",
  "apninfo": "fv1.deutschebahn.com,-1,-1",
  "technology": "lte"
}

Nice!