I'm trying to troubleshoot some problems with users being blocked from our website by CloudFlare. We run a Joomla 2.5 installation with RSFirewall. I have the list of IP blocks that CloudFlare uses, but I'm not versed enough with IP block math to figure out whether several of the addresses that are currently showing in the blacklist are actually CF servers. For example, the following IP is in our blacklist:

And CloudFlare uses the following block:

Based on what I read here it looks like that address is indeed a CloudFlare address and I need to remove it from the blacklist. Can anybody confirm whether I'm understanding it correctly or not? Thanks for your help.

  • I do not get to say this enough- but Welcome to the Webmasters StackExchange! The people here are excellent!
    – closetnoc
    Jun 30, 2014 at 17:29

2 Answers 2


If it helps at all the CIDR range converts to:

  • One up-vote! You were fast and precise. I just happen to have local CGI(s) that I use for my research that allows me to figure these things out quickly. Otherwise, you would have gotten the full nod. Thanks for answering!
    – closetnoc
    Jun 30, 2014 at 17:45
  • I'll upvote that as well once I have enough reputation. Thank you for confirming his answer and clarifying IP blocks for me!
    – Ant
    Jun 30, 2014 at 18:06

Yes. The IP address is CloudFlare within the IP address range of -


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