title: Can IP change during session?
body: <p>Can IP change during session?</p>
  
  <p>What about different engines (PHP, Django, Ruby, etc) ?</p>
  
  <p>PS: I don't quite understand what is 'dynamic ip' and how they are held by internet providers... And how sessions are broken...</p>
  
  <p><strong>Update:</strong>
  Should I track IP change for security? I'm currently working with PHP, so if the built in session system lacks security,  please provide some code and algorithms</p>