Comment 6 for bug 362970

I hit this problem too. I tried setting http_proxy from the xterm before launching synaptic with sudo, but sudo discards environment variables. If I'd had my brain in gear I might have tried "sudo su" and then set http_proxy before running synaptic, but I worked around the problem by creating a wrapper script for wget. However, this isn't robust because updates to wget will probably overwrite my script.

My opinion: the proxy that is in the synaptic configuration should be passed to the installer. It should not be necessary to define http_proxy externally, and it might be desirable under some circumstances to use a different proxy for synaptic than for general use (e.g. if a site is running a local mirror of the Ubuntu archives).

Also note: some of the strange "Sound doesn't work properly in Firefox after upgrade" bugs might be caused by this. As a result of the failed download, my upgraded system was still running an old Flash plugin. To try to fix the problem I deinstalled and reinstalled Flash, and that's when I discovered the download was failing.