title: Different session ID every time session_start is executed
body: <p>I have the following source code</p>
  
  <p>session1.php</p>
  
  <pre><code>&lt;?php
  
  session_start();
  echo session_id();
  
  ?&gt;
  </code></pre>
  
  <p>session2.php</p>
  
  <pre><code>&lt;?php
  
  session_start();
  echo session_id();
  
  ?&gt;
  </code></pre>
  
  <p>when I access session1.php then access session2.php, I get a different ouput.</p>
  
  <p>Why is this doing it?</p>