Cloudflare-Custom-Hostname-Verification

seo Cloudflare-Custom-Hostname-Verification

Cloudflare hostname verification crawler

About this crawler

Cloudflare-Custom-Hostname-Verification is a web crawler identified by the regular-expression pattern Cloudflare-Custom-Hostname-Verification in the User-Agent request header. It is categorised as seo. Use the regex above to detect, log, allow, or block Cloudflare-Custom-Hostname-Verification traffic in your web server, CDN edge rules, or robots.txt.

Block-rate · top 25k sites

No block-rate data for this crawler.

Technical details

Name
Cloudflare-Custom-Hostname-Verification
Pattern
Cloudflare-Custom-Hostname-Verification
Tags
seo
Reference
https://knownagents.com/agents/cloudflare-custom-hostname-verification
Added
2026/04/26
rDNS suffixes
.cloudflare.com
Instances
1 known sample(s)

rDNS verification (FCrDNS)

Verify a request is genuinely Cloudflare-Custom-Hostname-Verification 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.

Sample User-Agent strings

Mozilla/5.0 (compatible; Cloudflare-Custom-Hostname-Verification; +https://www.cloudflare.com/)

Block this crawler

robots.txt — disallow Cloudflare-Custom-Hostname-Verification:

User-agent: Cloudflare-Custom-Hostname-Verification Disallow: /

Apache .htaccess — return 403:

RewriteEngine On RewriteCond %{HTTP_USER_AGENT} Cloudflare-Custom-Hostname-Verification [NC] RewriteRule .* - [F,L]

Nginx — return 403 inside a server block:

if ($http_user_agent ~* "Cloudflare-Custom-Hostname-Verification") { return 403; }
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