Not much, but in this blog post, you can expect the easiest way How to get CloudFlare Visitor IPs in PHP programming.
As a webmaster, we always want to improve the website performance with CDN, so that I decide to go with CloudFlare. But we usually meet the problem CloudFlare with website/forum spam what we can’t check spam via visitors IPs because we are under CloudFlare proxy server.
Very simple with this PHP code
$ip = $_SERVER['HTTP_CF_CONNECTING_IP'];
If you want to get the real IP value from cloudflare to your PHP source in the way what you don’t have to change anything in coding but the system still run base on the real visitors IPs, you can use this way:
$_SERVER['REMOTE_ADDR'] = $_SERVER['HTTP_CF_CONNECTING_IP'];