Description
This article addresses an issue where the captive portal on Android devices closes abruptly after authentication, often before the user is redirected to the intended redirection webpage post-authentication.
Scope
FortiOS.
Solution
The FortiGate captive portal is configured for wifi users to access the internet. While the setup successfully redirects users to a designated page post-authentication on most devices(Windows, IOS), an issue occurs on Android devices where the default captive browser closes immediately after completing the authentication process.
When the user connects to the Wi-Fi, an authentication pop-up appears: the user is authenticated and if the authentication is correct it should redirect to a URL predefined but instead the Captival portal page closes as below.
The captive portal page pops up.
When testing with Android phones, connecting to the SSID triggers a notification from the OS to 'sign in'. A dropdown window appears displaying the captive portal page, but after completing authentication, the captive portal page prematurely closes, and the browser does not remain open.
However, bypassing the notification dropdown and instead opening a browser to access a website prompts the captive portal page correctly, and the redirect occurs properly after authentication.
The main issue lies in how the redirect action interacts with the built-in Android OS captive portal popup.
On Android phones, the captive portal login page opens in the 'CaptivePortalLogin' app, where the default behavior is to close automatically after successful authentication. In some cases, after completing authentication and the redirect process, the browser or app closes automatically. This behavior is standard for Android and cannot be modified from the Fortinet side.
