I work on Ubuntu 12.04 with an internet connection using proxy. Lately the proxy address changed, and now suddenly I cannot connect to internet whatsoever. Strangely, the same proxy address does work on a windows machine. I know there is a bug concerning the system wide application of proxy settings, but that is not my problem. If I set the new proxy address in Firefox it just does not connect. But in the network manager I can see that there is a connection.
Any clues how to make proxy work on Ubuntu?