title: how to change session id after login in asp.net
body: <p>I have a website that's using forms authentication and membership. A user must have cookies enabled to use the site. I've been asked to change the code so that the session id is changed as soon as a  user logs in. Aparently this will protect against a Session Fixation attack (<a href="http://en.wikipedia.org/wiki/Session_fixation" rel="noreferrer">http://en.wikipedia.org/wiki/Session_fixation</a>). Does anyone know how I can change the session id without losing the whole session ? PHP has a specific method for doing this but I can't find a .NET equivalent.  </p>