Getting all of Ubuntu to talk through a NTLM proxy
NTLM proxies are relatively common corporate web proxy. It takes special software to pass through it, unfortunately. One must essentially log into an NT domain to get to the web past the proxy. By default, web browsers are the only software on Ubuntu Linux that know how to perform the complex handshake. Many core tools (like apt, etc) cannot do what they need — and your system can’t download software updates.