This script forces a user to authenticate by using Basic Authentication. If you want to force a user to login using NT Challenge/Response Authentication, then replace the Response.AddHeader statement in the script with the following one:
Response.AddHeader "WWW-Authenticate","NTLM"
<%
authUser = TRIM(Request.ServerVariables("AUTH_USER"))
IF authUser = "" THEN
Response.Status = "401 Not Authorized"
Response.AddHeader "WWW-Authenticate", "Basic Realm=""SUPEREXPERT"""
Response.End
END IF
%>
<html>
<head><title>Password Please</title></head>
<body>
<font face="Arial"size="4" color="blue"><b>
Welcome <%=authUser%>! <br>Feel free to view this page.
</b></font>
</body>
</html>