title: Passing Windows User Credentials to Web Service
body: <p>I have a ASP 3.5 web forms app using windows authentication that needs to call a soap based web service (the SSRS 2005 report service) which uses integrated windows authentication. However the call to the web service from the asp backend keeps throwing a 401 error. 
  If I turn on anonymous authenticatoin on the web service it works ok using the IUSR_xxx account however I want it to connect using the windows account of the user accessing the asp web app. How can I pass through the windows user credentials?</p>