Comment 5 for bug 1727237

All captive portal wifi connections are failing with Ubuntu 17.10. This was confirmed on two different captive portals which both worked just fine with other devices. The solution was to go back to Ubuntu 17.04.

You get to the portal page, put in whatever info, then afterwards the redirect wouldn't redirecting properly. This failed in both Chromium and Firefox, and with both "use system proxy" as well as "automatic proxy" settings. Manual proxy configuration settings weren't tried, so I can't confirm if this might be a problem relating to the proxy pac file or not.

Either way this is a pretty critical issue since it seems all captive portals don't work, making Ubuntu 17.10 on laptops pretty broken at the moment.