What is gstatic generate 204 captive portal login ISP page

Everyone on the planet might some time came across generate_204 captive portal login page, What is it actually? have you ever doubted! Gstatic Generate_204 captive portal is an Network Portal Detection service bundled with Google related services and with hardware devices like Android smartphone, Android tablet, Android TV, Google TV, Google Chrome, Google Chrome background services,  Chromebook, Chrome OS Shill and other Chromium services.   

Amazon Affilate

Amazon Prime Day