该函数将获取用户的真实 IP 地址，即便他使用代理服务器。
function getRealIpAddr() 
{ 
    if (!emptyempty($_SERVER['HTTP_CLIENT_IP'])) 
    { 
        $ip=$_SERVER['HTTP_CLIENT_IP']; 
    } 
    elseif (!emptyempty($_SERVER['HTTP_X_FORWARDED_FOR'])) 
    //to check ip is pass from proxy 
    { 
        $ip=$_SERVER['HTTP_X_FORWARDED_FOR']; 
    } 
    else 
    { 
        $ip=$_SERVER['REMOTE_ADDR']; 
    } 
    return $ip; 
}