Ok, so it sounds like you work somewhere that has installed some BigBrotherWare on your computer. In order to get web pages, you have to talk to BigBrother, and he wants you to authenticate first. The Proxy-Authenticate header is not being sent to the web site, it's going to your company-installed security software. It sounds like you're going to either install LWP::Authen::Negotiate, or rip some chunks out of it and stick them in your program. Shouldn't be too hard either way, since it's a pure-perl module.