Captive portal not closing after authentication

[brightmarema]

hie guy,

i am having a bit of a challenge with captive portal on a Fortigate 100f that is running firmware 7.2.4. After authentication the captive portal page doesn't close but authentication would have been completed and users can browse the internet just fine. Issue is that, with the captive portal still open user assume the authentication did work and they proceed to try to authenticate again but now the web page loads and returns a " this page isn't working <ip> didnt send any data . i would appreciate any assistance as to why this could be happening and a way to fix it.

thank you in advance.

[pminarik]

There is one specific case where I recall this happening, and I think it might be worth it for you to check.

Some client devices/browsers probe for portals by requesting a page that returns a HTTP 204 code ("no content"), such as http://google.com/generate_204 . When such "page" is loaded in browser, it looks as if nothing at all has happened.

When authentication is done, the captive portal by default redirects to the originally requested page.

If you combine these two facts, you will see the behaviour where authentication is done, and the portal gives a redirect to the originally requested "204-generating" webpage, but seemingly nothing will happen as the browser has nothing to display (204 has no content), and visually the page will still show the captive portal.

If you'd like to confirm if this is your case, I would recommend that you trace the flow of pages and resources being loaded with the developer tools in your browser opened to the Network section, so that you can review what's being requested. If a 204 page is involved, you should see it there.