Goal: enforce captive portal authentication overHTTPSfor guests.

On FortiGate/FortiAuthenticator captive portal setups:

HTTP redirectis used so that when a guest browses to any HTTP site, their request is redirected to theportal URL.

Theportal URLitself must beHTTPSif you want a secure login page.

FortiOS captive portal and firewall authentication guidelines recommend:

EnablingHTTP redirectso unauthenticated HTTP traffic is transparently sent to the portal.

Configuring theportal URL with HTTPS, often referencing a certificate on FortiGate or FortiAuthenticator.

Therefore:

A. Enable HTTP redirect in the user authentication settings.✔This ensures unauthenticated HTTP requests are redirected to the (now HTTPS) portal.

D. Update the captive portal URL to use HTTPS on FortiGate and FortiAuthenticator.✔This makes the login itself secure (TLS-protected).

Incorrect:

B– You don’t need a new SSID; the same SSID can use HTTPS portal.

C– Disabling HTTP admin access on the SSID doesn’t control the captive portal scheme; HTTPS enforcement is done by the portal configuration and redirect, not by admin-access flags.