Comment 14 for bug 48682

Gianfranco,
First, environment variables do not support proxy exceptions. Those are hosts which must not be reached through the proxy but through direct connection.
Second, I can't work using environment variables as this would require to logout/login which is not allowed in my case. In fact, I use GNU/Linux as it avoids those painfull reboots and logout/login which are a not negligible part of other OSes users' lives.

Ancoron,
I agree with you.

Maybe the solution is a fake-proxy-relay ? It would be installed by default under [K]ubuntu and which would be the single point of configuration where to set the real proxy configuration. Then any package would be preconfigured to use it as its proxy, without having to keep the settings up to date across the applications.