CloudFlare-Prefetch
CloudFlare prefetch web crawler bot
About this crawler
CloudFlare-Prefetch is a web crawler identified by the regular-expression pattern CloudFlare-Prefetch in the User-Agent request header. It is categorised as seo. Use the regex above to detect, log, allow, or block CloudFlare-Prefetch traffic in your web server, CDN edge rules, or robots.txt.
Block-rate · top 25k sites
0.065%
Technical details
- Name
- CloudFlare-Prefetch
- Pattern
CloudFlare-Prefetch- Tags
- seo
- Reference
- https://developers.cloudflare.com/speed/optimization/content/prefetch-urls/
- Added
- 2024/12/17
- rDNS suffixes
.cloudflare.com- Instances
- 1 known sample(s)
rDNS verification (FCrDNS)
Verify a request is genuinely CloudFlare-Prefetch with forward-confirmed reverse DNS: the client IP's PTR record must end in one of the suffixes below and a forward A/AAAA lookup of that hostname must return the same IP. UA strings alone are spoofable; FCrDNS is not.
.cloudflare.com
Sample User-Agent strings
Mozilla/5.0 (compatible; CloudFlare-Prefetch/0.1; +http://www.cloudflare.com/)
Block this crawler
robots.txt — disallow CloudFlare-Prefetch:
User-agent: CloudFlare-Prefetch
Disallow: /
Apache .htaccess — return 403:
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} CloudFlare-Prefetch [NC]
RewriteRule .* - [F,L]
Nginx — return 403 inside a server block:
if ($http_user_agent ~* "CloudFlare-Prefetch") {
return 403;
}
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