We have a Forefront TMG proxy at work. When I configure some command line tools with the proxy address, I often include my credentials using username:password@proxy-address
but it never works.
I suspect that this only works for Basic Authentication but the TMG proxy doesn't have this setup, I have seen the headers in the challenge response.
Does TMG support Basic Auth and will it use AD credentials or will it use some kind of internal list of users?
Yes.
-- http://www.isaserver.org/articles-tutorials/configuration-security/Authenticating-Outbound-Web-Traffic-TMG-Firewall-Protected-Networks.html