Login page login.asp:
<%
if request.Form.count>0 then
session("username")=request("username")
application(session("username"))=session.SessionID
response.Redirect("index.asp")
end if
%>
<form method=post action="">
<input type="text" name="username"><input type="submit">
</form>
Other pages that require authentication index.asp:
<%
if application(session("username"))=session.SessionID then
response.Write("Already logged in")
else
response.Write("Not logged in")
end if
%>