How do I authenticate over a domain while doing apt-get update? [duplicate]

Question

I am getting various 401 auth errors when trying to sudo apt-get update. I am connected to my corp vpn and have an SSH into my Ubuntu machine.

How can I authenticate using my network login/pw to complete 1) apt-get update and 2) updates to a newer dist?

::snip::

W: Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/oneiric-security/multiverse/source/Sources 401 Authorization Required [IP: 91.189.92.200 80]

E: Some index files failed to download. They have been ignored, or old ones used instead.