filter_var过滤私有ip

$host = "192.168.1.1";

var_dump(filter_var($host, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 | FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE));
echo "<br>";

$host = "127.0.0.1";

var_dump(filter_var($host, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 | FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE));
echo "<br>";

$host = "120.78.66.99";

var_dump(filter_var($host, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 | FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE));
echo "<br>";

$host = "172.17.2.3";

var_dump(filter_var($host, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 | FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE));
echo "<br>";
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bool(false) 
bool(false) 
string(12) "120.78.66.99" 
bool(false)