[jb605]

It might also be helpful to add IP based cookie:

PHP Code:

  if (preg_match('/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}/',$_SERVER["HTTP_HOST"]))
 {
    // this is a ip address
    $vboptions['cookiedomain'] = "." . $_SERVER["HTTP_HOST"];
} 


Or something similar