Apple CNA is not an "Inspectable application" in Web Inspector

Question

Level 1

4 points

Apple CNA is not an "Inspectable application" in Web Inspector

Hi Community,

To investigate an issue (AUP page looping) with a wireless Captive Portal a vendor (Cisco) requested the HAR file from the iPhone trying to connect.

The problem is that the Captive Portal is opened by Apple CNA and this apparently is NOT an "Inspectable Application", nothing appears in Web Inspector menu on MBP when the CNA "mini-browser" opens.

However if I manually open the Captive Portal with Safari or another browser, that shows in Web Inspector but the issue doesn't happen so even if I can collect HAR file for that browser is not useful to the vendor.

We suspect something is wrong with a JS on that Captive Portal but we can't prove it without HAR file.

Is there a way around this limitation?

iPhone SE 3rd running 18.6.2

MBP M2 running Sonoma 14.7.7

The two are connected via USB cable.

Thank you.

FedS

iPhone SE, iOS 18

Posted on Sep 7, 2025 4:59 PM

Reply

Answer 1

Top-ranking reply

SravanKrA

Level 10

431,612 points

Sep 7, 2025 11:40 PM in response to Fed_S

ChatGPT says:

The Captive Network Assistant (CNA) “mini-browser” is not a real Safari process — it’s a very stripped-down web view with no developer hooks, and Apple explicitly prevents it from being inspected via Web Inspector. That’s why nothing shows up when you plug your iPhone into the Mac.

Vendor-side workaround

If Cisco just needs a HAR-like log of the exact CNA session:

Tell them upfront CNA cannot be inspected.
Provide them with either a proxy capture or a pcap file. Many vendors accept these since HAR is just structured HTTP(S) logging.
If they insist on HAR, Charles Proxy and Fiddler both can export captures to HAR format.

Reply

Answer 2

Fed_S Author

Level 1

4 points

Sep 9, 2025 7:00 PM in response to SravanKrA

Thanks SravanKra,

Useful knowledge. With pcap, problem is that traffic with Guest portal is HTTPS. Charles Proxy/Fiddler would be good options but I don't have that sort of time right now, plus not sure if a MDM-managed iPhone would allow installing/using either. Thanks a lot anyway.

FedS

Reply