ho l'header costruito così, perchè nei dettagli della mail di outlook express leggo "Return-Path: <me@localhost.com>"?Codice PHP:
$headers = 'MIME-Version: 1.0' . "\r\n";
$headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
$headers .= 'From: <info@abc.it>' . "\r\n" .
'Reply-To: <info@abc.it>' . "\r\n" .
'Return-Path: <info@abc.it>' . "\r\n";
if(mail($addr, $subject, $message, $headers)) echo "OK
"; else echo "Failed
";