title: Using session ID to validate a user on secure webpages
body: <p>This is a follow up to a question I posted earlier, but was unclear then. I hope I can be more clear now.</p>
  
  <p>I'm using ASP.NET and C# to validate a user after login on all secure pages. I <em>should</em> be able to do this without touching the web.config files so please avoid any such solutions that involve editing the web.config file. After some debugging, I've found that wehn a user logs in, the secure pages can be accessed by any other person (without logging in) from another computer, or simply on the same computer but in a different browser. This is obviously bad, so i'm wondering how I can use the initial session ID of a valid user to protect all subsequent page_load's from other users who have the direct page path, but not a valid login.</p>
  
  <p>At the moment, the only check I do in all secure page_load functions is to check wether <code>MySession.GetSessionId()==null</code>. How can I use this value returned by <code>GetSessionId()</code> to check against what the initial session ID value was upon logging in?</p>