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 your based on you MAC address.
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 your based on you MAC address.
The config is server-side (router).