title: Auto Signin with Active Directory Account in c# ASP.Net Website
body: <p>We have a website which can be used as intranet for Staffs and internet for outside people.   All our staffs accounts are in Active Directory. So, when the internal staffs browse the URL (For eg. <a href="http://app.abc.com" rel="nofollow">http://app.abc.com</a>), they should be automatically signed in by using their AD accounts.</p>
  
  <p>However, for external users, they have to use their username and password. I could do this part easily just by looking up the database and make authentication.</p>
  
  <p>I would like to know how I could auto sign in the AD users into the website.</p>