get user Active Directory details

I am building a simple intranet site and I want to get the user's Active Directory.

What steps do I need to take on the IIS side for this to work? Are any changes required to my web config?

I would appreciate a detailed explanation, as this is giving me a hard time.

I have tryed things like this

Request.LogonUserIdentity.Name.ToString

also

HttpContext.Current.User.Identity.Name

the users will not login the page should be able to get the credentials without them typing their username and password

windows authentication in my we开发者_JS百科b config throws an error and causes my page not to work

This might be a good starting point for you: Recipe: Enabling Windows Authentication within an Intranet ASP.NET Web application

or this: Active Directory Services: PrincipalContext — What is the DN of a “container” object

As @Joel Ehterton said, more details of exactly what you're trying to do would be helpful.