cloudflare/CloudFlare-Tools — pull request #9 by jamescf (2012-05-11 22:19:14+00:00)
Title: Dynamic IP address list pulling, caching of IPs to text file in case of cloudflare.com downtime.

1) Pull IPs from live IP list on https://www.cloudflare.com/ips-v4
2) Cache the list to text file, ipv4_list.txt and use this unless the text file has expired (1 day from time of last pull of IPs from live IP list).
3) ipv4_list.txt must have write permissions from the plugin itself.
4) If everything is failing, default to using statically generated IP list hard-coded into cloudflare.php until able to grab the live IP list again.