User roles and single sign on

[TheEarthWillShake]

I'm creating a web app that will have 3 user roles.

Admins (Can view all)
Project Managers (only view ProjMan folder)
Readers (Only view Reader folder)

The way I want to log users onto the site is via this which gets the Windows username that is used to authenticate a Windows user onto the computer.

//******

string temp;
temp = Request.ServerV ariables["LOGON_USER "];
Label1.Text = temp;

//*****

It allows me to catch the user name of the Windows machine.

When I catch it I want to see if it exists in the database and if it does, allow them to go onto the site, only a select few people are allowed on the site, that's why I want it to be compared to a database.

Does anyone have any guides on this?

[Plater]

Does this help at all?

http://msdn.microsoft.com/en-us/library/ms998314.aspx

Somewhere I thought there was a video that stepped you through all of this stuff, but I cannot find it anymore.