Apple’s captive portal PIA and other curious WiFi behaviour

TidBITS Talk
1

I post this mostly out of curiosity, because it’s not a big problem for me, but I’d welcome any helpful suggestions, too.

A hospital where I attend has a guest network (slower than molasses, but better than nothing for patients). I have a MBAir M2 with Ventura and an iPhone with iOS 16.2. My ISP contract gives me 150Mbps/20Mbps. Whenever I open my Mac, the captive portal window opens and tells me I can’t connect to the guest portal, and there seems to be no way I can get rid of that barrier. Nor can I use my usual ISP. When I use my phone, it automatically connects to my high-speed ISP WiFi. I can of course tether my Mac to my phone, which then switches from WiFi to LTE.

The Mac’s captive portal is for security, but I don’t need that security at the hospital. For me it’s a PIA, and I wish it could be disabled, but there seems to be no way with Ventura. But it seems strange (though I’m happy) that my phone connects directly to my ISP, totally ignoring or ignored by the hospital’s guest network. But then why does tethering only use LTE?

2

Tethering can only use WiFi while you’re already connected to WiFi because tethering requires two network connections. So,your device connects to your phone over wifi, so the phone needs to connect to another network over another network connection - in this case, mobile data.

3 Likes
3

Thanks for that, which I didn’t know. Now I can save my mobile data allotment for when I really need it, and not just use it up with abandon.