Jan 1, 2010 · I found this old Thread while google'ing for generate_204 as Android seems to use this to determine if the wlan is open (response 204 is ...

adb shell settings put global captive_portal_https_url https://www.google.cn/generate_204 ... Make sure to use http url with http setting, and https url with ...

The cross icon disappears in cellular data icon if my network can't access "connectivitycheck.gstatic.com/generate_204" but can access "captive.v2ex.co/ ...

Nov 27, 2017 · ' A small list of usable captive portal server URLs in mainland China (personally tested). https://captive.v2ex.co/generate_204 (hosted ...