PHP Get Real IP Address

function getRealIpAddr()

{

    if (!empty($_SERVER['HTTP_CLIENT_IP']))   //check ip from share internet

    {

      $ip=$_SERVER['HTTP_CLIENT_IP'];

    }

    elseif (!empty($_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;

}

ที่มา
http://roshanbh.com.np/2007/12/getting-real-ip-address-in-php.html