$good_ip = "192.168.0.1";
$bad_ip = "1.334.10.10";
$regex = "^(([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]).){3}.([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$" ;
if (ereg($regex, $good_ip)) {
echo "'" . $good_ip . "' is a valid ip address.\n";
} else {
echo "'" . $good_ip . "' is an INVALID ip address.\n";
}
if (ereg($regex, $bad_ip)) {
echo "'" . $bad_ip . "' is a valid ip address.\n";
} else {
echo "'" . $bad_ip . "' is a INVALID ip address.\n";
}
?>