title: Sessions getting mixed up PHP
body: <p>Hi we have been operating a system for about 500 users online on one centralized dedicated server. Our application is coded in PHP. Recently when we have a reasonable load of about 100 -150 users sessions start getting mixed up. For instance if a user logins as A after a while his session switches to User B who is also logged in. The system has been in operation for over a year and this is the first time we are facing the problem. </p>
  
  <p>The server is running Centos. Is this anything on the server end or is it something in the code. Any help much appreciated.</p>