Access Active Directory from web application
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I'm really stuck on this problem. Basically, I have a Windows 2008r2 server which runs Active Directory. On another server (not in the same domain) runs a MVC3 Web Application. What I want to do is to authenticate users with active directory as well as get some basic information, i.e employeeId. I also want the users to be able to change their password through this web app. 

This is a custom web application, and I don't want to use stuff like exchange.

I have somewhat managed to achieve this goal by using ad connection string in web.config or specifying administrator username and password in my code. However, this is not intuitive considering security and that the administrator account may change password at some point.

I might be wrong, but I guess what I want to do is to somewhat do requests to AD with the role of administrators.

Is there any way I can achieve this?

Thanks in advance!
Cheers