Security architecture and design

A denial-of-service attack is a malicious attempt to overwhelm an online service and render it unusable. Explain three issues associated with combining a third party like Cloudflare (https://www.cloudflare.com) to prevent Dos attacks. Does CloudFlare play well with recaptcha? Search the Internet and elsewhere for current issues with using third-party services for DoS. 

Requirements:I recommend your posting to be between 200-to-300 words. All posts must contain a properly formatted in-text citation and scholarly reference.