This just refused to work because the flashplugin-installer that actually downloads the packet doesn’t honor the http_proxy environment variable to I had to do a little hack to get this going. It’s actually pretty simple: download the file and serve it from localhost so we don’t need the proxy at all.

First shell:

• mkdir /tmp/flash
• cd /tmp/flash
• wget http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_11.2.202.310.orig.tar.gz
  ==> or whatever version YOU need
• python -m SimpleHTTPServer 80

Second shell:

• unset http_proxy
• vi /etc/hosts
  ==> add an entry so that “archive.canonical.com” points at 127.0.0.1 and save the file
• aptitude install flashplugin-installer
• vi /etc/hosts and remove the newly added entry

Stop the python http server and you’re done.