【www.gdgbn.com--安卓教程】

获取用户IP地址与判断真实IP
function getIp() {
    if($_SERVER["HTTP_CLIENT_IP"])
    {
        return $_SERVER["HTTP_CLIENT_IP"];
    } elseif ($_SERVER["HTTP_X_FORWARDED_FOR"]) {
        return $_SERVER["HTTP_X_FORWARDED_FOR"];
    } else {
        return $_SERVER["REMOTE_ADDR"];
    }
}

function get_real_ip()
{
        $ip=false;
        if(!empty($_SERVER["HTTP_CLIENT_IP"]))
        {
                $ip = $_SERVER["HTTP_CLIENT_IP"];
        }
        if (!empty($_SERVER["HTTP_X_FORWARDED_FOR"]))
        {
                $ips = explode (", ", $_SERVER["HTTP_X_FORWARDED_FOR"]);
                if ($ip)
                {
                        array_unshift($ips, $ip); $ip = FALSE;
                }
                for ($i = 0; $i < count($ips); $i++)
                {
                        if (!eregi ("^(10|172.16|192.168).", $ips[$i]))
                        {
                                $ip = $ips[$i];
                                break;
                        }
                }
        }
        return ($ip ? $ip : $_SERVER["REMOTE_ADDR"]);
}

本文来源：http://www.gdgbn.com/shoujikaifa/21667/