Proxy Server work around
When you click on a link and get the 404 page, if you remove the "http://proxy.medlib.iupui.edu/auth.aspx?url=" portion of the URL, you should be able to get to the target site. If you still have problems accessing resources, it's likely due to being off-campus. Connecting to the VPN should resolve that issue. Instructions on how to connect to the VPN when off campus can be found here, http://library.medicine.iu.edu/about/wireless-vpn-access.