Magento Show Remote IP When using cloudFlare

/app/code/core/Mage/Core/Helper/Http.php

function getRemoteAddr  

if ( $_SERVER["HTTP_CF_CONNECTING_IP"] ) {
    $this->_remoteAddr = $_SERVER["HTTP_CF_CONNECTING_IP"];
}

http://www.tall-paul.co.uk/2012/03/02/magento-show-remote-ip-when-using-cloudflare/