Comment 8 for bug 462379

Forgot to mention that the proxy was preseeded:

ubiquity mirror/http/proxy string http://10.0.2.9:3142/

In IRC, xnox suggested configuring a global proxy in network-manager, and that does work for the language packs:

Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 10.0.254.133:58356 10.0.2.9:3142 TIME_WAIT -
tcp 0 0 10.0.254.133:893 10.0.2.1:2049 ESTABLISHED -
tcp 0 0 10.0.254.133:58357 10.0.2.9:3142 ESTABLISHED 10345/http
tcp 0 0 10.0.254.133:57483 91.189.92.60:80 ESTABLISHED 3667/python3

(In my case 10.0.2.9:3142 is not a general http proxy but only an apt-cacher-ng, so that does break e.g. Firefox in the live session, but it does work for installing.)

The http process is a child of plugininstall.py and runs in the host, not the target:

init───lightdm───lightdm───init───sh───udisks2-inhibit───ubiquity───log-output───plugininstall.p───http

His other suggestion was to disable downloading the language packs at install time. Preseeding "ubiquity pkgsel/install-language-support boolean false" does that, so that's a good workaround. (Not quite ideal, though, because /var/lib/update-notifier/user.d/incomplete-language-support-*.note aren't created; is that a bug?)

plugininstall.py already seems to respect some other apt settings, maybe it wouldn't be hard to teach it about mirror/http/proxy as well? If I find time I'll see about a patch. Low importance, anyway.