What OS version on iPhone are you trying?
There is a "Bug" / "Feature" - how ever you will call it - which changed the behaviour with iOS16. It will use the external public DNS for request no matter if you give your internal via DHCP to the iPhone.
The public DNS Server doe not know your Captive Portal IP Address so it will not be resolved.
Have this meanwhile two time in customer situation where we used the Firewall to redirect DNS request to internal domain to internal DNS Server.
Could be the issue here as well.
You will see it when you are doing a packet capture.
See -
https://developer.apple.com/forums/thread/715416
Original Message:
Sent: Jan 17, 2023 03:20 AM
From: remnaz
Subject: IPhone cannot authanticate with Captive Portal
Yes I have a web auth service and android devices are not facing any problem.
Original Message:
Sent: Jan 16, 2023 08:22 PM
From: ProbeRequest
Subject: IPhone cannot authanticate with Captive Portal
Does an authentication from an android device result in a request in Access Tracker? Have you got a service setup for web auth login.
Original Message:
Sent: Jan 16, 2023 03:54 AM
From: remnaz
Subject: IPhone cannot authanticate with Captive Portal
Hi everyone,
I made a Self-registration page for guests and when I tried with android phones, it worked correctly. But whe I tried to connect with an IPhone, it didn't redirect the page. To solve this problem I enabled the 'Prevent CNA' property in Self-registration. After that, IPhone redirected the page and I tried to register an account. But when I tried to login, it redirected me to the registration page again. I checked the Acces Tracer but there was no request belong to IPhone. How can I solve this issue?