captive portal not launched automatically or no signin wifi popup displayed with some samsung phones

zied

Hello, I have an issue detected only on samsung s4 and j7 but ok on others (ios, lenovo, asus, huawei)
I installed a webserver with captive portal on a raspberry with a hotspot (nginx/apache2/lighttpd, hostapd, dnsmasq) when i connect to this wifi network a popup "Sign-in to network" is displayed or an auto launch of the captive portal page is done.
This behavior failed only on some samsung smartphone like s4 and j7, when i connect nothing happened!!! no popup nor auto display CP page
any proposition?

free4

@zied said in captive portal not launched automatically or no signin wifi popup displayed with some samsung phones:

Hello, I have an issue detected only on samsung s4 and j7 but ok on others (ios, lenovo, asus, huawei)
I installed a webserver with captive portal on a raspberry with a hotspot (nginx/apache2/lighttpd, hostapd, dnsmasq) when i connect to this wifi network a popup "Sign-in to network" is displayed or an auto launch of the captive portal page is done.
This behavior failed only on some samsung smartphone like s4 and j7, when i connect nothing happened!!! no popup nor auto display CP page
any proposition?

Yes : the problem is likely on your phone side, not captive portal side

All Android phones behave the same. When connecting to wifi :

If (not recieving HTTP reply 204 from  http://connectivitycheck.gstatic.com/generate_204 ) {
    openSignInToNetwork()
}

This is the behaviour on android for all android phones. Samsung, HTC etc...are working the same way, this is how Android has been designed.

The only notable exception to this are Android phones that are sold in mainland China. They are usually using https://connect.rom.miui.com/generate_204 or http://www.qualcomm.cn/generate_204 instead...because connectivitycheck.gstatic.com is blocked there, so the original test wouldnt work

My samsung (galaxy a8 2018) phone also handle captive portal like a charm. Maybe it could be related to your android settings? Did you check the value of captive_portal_detection_enabled / captive_portal_mode in android?

tripflex

One would assume that's how it should work, as 302 redirect seems to be standard for captive portal ... but I can confirm that Samsung devices for some reason -- do not follow this standard.

See here for more details:
https://android.stackexchange.com/questions/139588/captive-portal-detection-causing-phones-to-disconnect-from-wi-fi-in-intranet-env/208674#208674

Seems as though Samsung devices and their modified Android OS has changed the default handling to require some kind of response in the generate_204 instead of just using the code like mentioned above to trigger the captive portal login