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

Answer 1

A quick solution (error free)

function getClientIP()
{
    $ipaddress = 'UNKNOWN';
    $keys=array('HTTP_CLIENT_IP','HTTP_X_FORWARDED_FOR','HTTP_X_FORWARDED','HTTP_FORWARDED_FOR','HTTP_FORWARDED','REMOTE_ADDR');
    foreach($keys as $k)
    {
        if (isset($_SERVER[$k]) && !empty($_SERVER[$k]) && filter_var($_SERVER[$k], FILTER_VALIDATE_IP))
        {
            $ipaddress = $_SERVER[$k];
            break;
        }
    }
    return $ipaddress;
}