Services
Webpage which shows exactly your current IP as it seen by the web server::
http://connectivity.decagon.de/ip/
https://connectivity.decagon.de/ip/
Webpage which shows your position if your browser 'supports' this feature:
https://www.decagon.de/geoip.html
Webpage which can be used in Android phones and others to replace the built-in internet access check / captive portal check. (e.g. beginning with Android 6.0 the URL http://connectivitycheck.gstatic.com/generate_204 will be called) - This is a very nice tracking feature because this web page wil be accessed everytime when the phone get's a new (WLAN) connection !!! For further info see also www.kuketz-blog.de/android-captive-...
http://connectivity.decagon.de/generate_204
The same for Apple but it's not possible to configure this in Apple devices.
http://connectivity.decagon.de/ios
Webpage which shows your browser identification:
https://www.decagon.de/browser