My Ubuntu 16.04 did not work with @DB_Bahn's Wifi network out of the box. Here's what I did:
Step 1 Connect to the WLAN wifionice.
Step 2. Fire up your browser and open http://www.wifionice.de - at this point, I got an "unable to connect" message.
Step 3.. Open up a terminal (Ctrl-Alt-T on Ubuntu) and find out the IP address of www.wifionice.de