If you connect to the network and open firefox, it will display a toast to open the corresponding captive portals page. You can then login through that. Given that your VPN isn’t blocking unencrypted connections etc.
Extrapolation of partial knowledge warning
I assume the network advertises a captive portals url and identifies you based on your MAC address.
Most captive portals work by answering the DNS requests with the captive portal ip. This works only if the correct dns servers are configured and a lot of security features like dnssec, DOH, … are disabled.
I still cannot connect to captive portals for public WiFis, eg on train or hotel and I have no idea where the config comes from.
DNS? Resolve.conf? Systemd network manager? WTF?
(Probably for the best though, so I use my phone 5G and not these suss open networks )
If you connect to the network and open firefox, it will display a toast to open the corresponding captive portals page. You can then login through that. Given that your VPN isn’t blocking unencrypted connections etc.
Extrapolation of partial knowledge warning
I assume the network advertises a captive portals url and identifies you based on your MAC address.
The config is server-side (router).
I get “limited connection” I think when I try connect or “no internet”.
I don’t make it to load the portal page…
so maybe I’m not recieving at IP from the network?
I use this project (https://github.com/FiloSottile/captive-browser) which works most of the time.
Most captive portals work by answering the DNS requests with the captive portal ip. This works only if the correct dns servers are configured and a lot of security features like dnssec, DOH, … are disabled.
More info from the project author: https://words.filippo.io/captive-browser/