<?php
$auth = $_COOKIE['auth'];
header("Cache-Control:no-cache");
if( ! $auth == "ok" )
{
header("Location:login.php" );
exit();
}
?>
<html>
<head>
<title>Logged In</title>
</head>
<body>
You are logged in and can access all pages on this web site.
<a href="anotherpage.php"><br>Visit another page on this site ?</a>
</body>
</html>