How to get the client IP address in PHP [duplicate]

Answer 1

Like the following?

if (($ip=filter_input(INPUT_SERVER, 'REMOTE_ADDR', validate_ip)) === false or empty($ip)) {
    exit;
}
echo $ip;

---

PS

if (($ip=filter_input(INPUT_SERVER, 'REMOTE_ADDR', FILTER_VALIDATE_IP|FILTER_FLAG_NO_PRIV_RANGE|FILTER_FLAG_NO_RES_RANGE)) === false) {
    header('HTTP/1.0 400 Bad Request');
    exit;
}

All headers beginning with 'HTTP_' or 'X-' may be spoofed, respectively is user defined. If you want to keep track, use cookies, etc.