Like many, this institution I'm at uses a proxy. In Windows, you need to go to Internet Options & select "Automatically detect settings" for stuff to work, except for Firefox, which has the same setting in its own Options dialog.
In Ubuntu, this is all different. I've set the Network Proxy thing to Automatic, but it doesn't work. I also managed to find the wpad.dat file on the intranet, but it provided no useful information other than an IP address. This address is the same as the on the IT guy said is the IP of the proxy server. He told me to use the Manual setting & enter that IP address & port 8080.
That didn't work either. Nothing connects (btw, I'm using an ethernet connection).
I suspect that a .pac file is needed, but (as usual) the IT guys seem utterly clueless.