ExclusiveSecurityFilter.php

<?php
class ExclusiveSecurityFilter extends sfFilter
{
  public function execute($filterChain)
  {
        if($this->context->getUser()->isAuthenticated()
        && session_id() != $this->context->getUser()->getProfile()->getSessionId()
        && $this->context->getUser()->getProfile()->getLastLoginIp() != $this->context->getRequest()->getRealRemoteAddress()
        )
        {
      $this->context->getUser()->signOut();
      $this->context->getUser()->setFlash('error', 'Account is being used in another machine.');

      $this->context->getController()->redirect($this->context->getRequest()->getUri());

      throw new sfStopException();
        }

    $filterChain->execute();
  }
}