checkdnsrr always false

[danielle]

i want to enter an ip of a machine to see if it is in DNS it always sais 'no'. works ok if i enter the name server.

if (!$ip) {
echo "
<form action='$PHP_SELF' method='post'>
IP:
<input type='text' name='ip'>
<input type='submit' value='Look it up....'>
</form>";
}
else {

echo '<p>IP:'.$ip.'<p>';
if (checkdnsrr($ip, 'ANY'))
	echo "yes";
else
	echo "no";

}