Comment 5 for bug 1664399

I tried putting the config snippet in place on a new installation of Ubuntu GNOME 16.10 BEFORE booting into the installation for the first time. I also upgraded it to GNOME 3.22 first (from the gnome3-staging PPA). Then, when I logged in for the first time and tried connecting to a captive portal network from the GNOME initial setup wizard, it showed a tick mark but the NM icon remained a question mark and the Internet was inaccessible from the system until I turned Wi-Fi off and then on. I experienced a similar problem even when installing the snippet on an existing installation (as well as on a fresh one), after the second reboot or so - the icon would remain a question mark and the system did not connect until I rebooted.

Next I tried the following:-
 * Commented out the interval and response lines in the config file AND,
 * Commented out dns=dnsmasq in /etc/NetworkManager.conf

The interval and response are set to default values if missing. This is working correctly, without the problems mentioned above, on a fresh installation. I don't know which of the two makes it work, but there are a further two points:-
 * The changelog for network-manager 1.2.4-0ubuntu1 includes the following: "Switch back to dns=dnsmasq for Ubuntu 16.10. We still don't have a DNS plugin for resolved, and don't want to break domain-specific DNS servers for the final release." I don't know what exactly is impacted by disabling dnsmasq.
 * Maybe the response value in the config file needs to be enclosed in (double) quotation marks? I don't know the syntax for values with spaces in them.

Since it's working now, I'm a bit wary of experimenting with these two settings.