I'm using Firefox 102 on Ubuntu Mate 20.04 (the vanilla one from apt), but I think I've experienced the same with a couple of previous versions too ... So, I've sat in on… (funda kabanzi)
I'm using Firefox 102 on Ubuntu Mate 20.04 (the vanilla one from apt), but I think I've experienced the same with a couple of previous versions too ...
So, I've sat in one Espresso House in Denmark; tried to connect to their public Wi-Fi with Firefox in private mode, captive portal went fine, and I was on the Internet. Apparently I had gotten a danish IP address there, since google.com thereafter was in danish.
Now, I sit in a different Espresso House, also in Denmark; however, here, captive portal does not work; in the sense that:
As shown on first screenshot, first I get "You must log in to this network before you can access the Internet.", and I get a "Open network login page" button.
I click on the "Open network login page" button, I can see browser wants to load http://detectportal.firefox.com/canonical.html - but in the end, I do not get the Espresso House login page, but instead I get a redirect to https://support.mozilla.org/en-US/kb/captive-portal , where the "You must log in to this network before you can access the Internet." still stands, but there is no more "Open network login page" button (as shown on the second screenshot)
If I restart the browser in this shop, I think I get the exactly same process - Espresso House wi-fi login page never gets shown, only the https://support.mozilla.org/en-US/kb/captive-portal ...
Strangely, at this point, I do get access to the internet through a browser - but google.com is then in swedish, which I guess means, that there is some sort of a VPN of that shop's wi-fi to Sweden. On the other hand, I don't get internet elsewhere on my computer - for instance, if I want to do `sudo apt update` from the command line, I get errors like "Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)" - which is what I otherwise get in (the first mentioned) Espresso House, before I've connected to wi-fi via captive portal (once I connect to wi-fi via captive portal there, `sudo apt update` or any other network access from command line is fine).
(Note: my android phone in the same shop, does indeed show Espresso House Wi-Fi login prompt upon Wi-Fi connection, and I can login there fine).
Why does this happen, and how can I force Firefox to show me the actual captive portal so I can login to Wi-Fi - instead of redirecting me to https://support.mozilla.org/en-US/kb/captive-portal ?