SUMMARY Demonstrative video: https://youtu.be/LuaVOYQOw3g When the notification prompts you to log in, the button takes you to https://networkcheck.kde.org/. Normally when the network login blocks all traffic, it automatically redirects you to the login page. If the network only blocks UDP before you log in, the web request goes through to that page and it only displays OK. I think the notification should direct you straight to the default gateway like it ddoes on android. STEPS TO REPRODUCE 1. Be in a network that requires login but only Blocks UDP 2. Click on the desktop notification to log in OBSERVED RESULT You get directed to https://networkcheck.kde.org/ and the webpage only displays OK while you never get to log into your wifi EXPECTED RESULT The notification should direct you to the default gateway where the login resides SOFTWARE/OS VERSIONS Linux/KDE Plasma: SteamOS Holo (available in About System) KDE Plasma Version: 5.23.5 KDE Frameworks Version: 5.90.0 Qt Version: 5.15.2 ADDITIONAL INFORMATION
Pretty sure this is the issue I was hitting with free airport wifi on a recent trip
Thankfully I was trying to use wireguard and bittorrent so I was able to catch the root cause
Apparently Android supports RFC 8910 (https://developer.android.com/about/versions/11/features/captive-portal) and uses this to determine where to send you. It looks like support for this is stalled in NM but known (https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues/1305) and actually exists in systemd-networkd (https://github.com/systemd/systemd/pull/28132). It looks like this would be more proper than using the default gateway if ever implemented in NM. I don't know if using the default gateway is actually appropriate.