How to get Real IP from Visitor? PHP Code

http://stackoverflow.com/questions/13646690/how-to-get-real-ip-from-visitor

 function getUserIP1() {
return $_SERVER['REMOTE_ADDR'];
 }

 function getUserIP2() {
    if( array_key_exists('HTTP_X_FORWARDED_FOR', $_SERVER) && !empty($_SERVER['HTTP_X_FORWARDED_FOR']) ) {
        if (strpos($_SERVER['HTTP_X_FORWARDED_FOR'], ',')>0) {
            $addr = explode(",",$_SERVER['HTTP_X_FORWARDED_FOR']);
            return trim($addr[0]);
        } else {
            return $_SERVER['HTTP_X_FORWARDED_FOR'];
        }
    }
    else {
        return $_SERVER['REMOTE_ADDR'];
    }
 }

function getUserIP3()
{
    $client  = @$_SERVER['HTTP_CLIENT_IP'];
    $forward = @$_SERVER['HTTP_X_FORWARDED_FOR'];
    $remote  = $_SERVER['REMOTE_ADDR'];

    if(filter_var($client, FILTER_VALIDATE_IP))
    {
        $ip = $client;
    }
    elseif(filter_var($forward, FILTER_VALIDATE_IP))
    {
        $ip = $forward;
    }
    else
    {
        $ip = $remote;
    }

    return $ip;
}