What is CloudflareCustomHostnameVerification?

CloudflareCustomHostnameVerification is a bot in the SEO crawlers category.

Bot name
CloudflareCustomHostnameVerification
Operator
Unknown
Category
SEO Crawlers
Type
Bot
Respects robots.txt
Not confirmed
robots.txt user agent
Cloudflare
Signs requests (Web Bot Auth)
No

About CloudflareCustomHostnameVerification

Cloudflare Custom Hostname Verification service.

SEO crawlers map links, keywords and technical issues for SEO tools and backlink databases. They help the tool's customers, often your competitors, rather than you. Rate limit or block the ones you do not use.

CloudflareCustomHostnameVerification user agent

CloudflareCustomHostnameVerification identifies itself with this user agent string:

  • Cloudflare Custom Hostname Verification

Anyone can copy a user agent string. Transfon Security also checks where each request comes from, so a request that claims to be a known crawler but comes from the wrong network is treated as a fake, not as the real crawler.

How to block CloudflareCustomHostnameVerification in robots.txt

We have not confirmed whether CloudflareCustomHostnameVerification follows robots.txt. Add a rule, then check your logs to see that it stopped. robots.txt is a plain text file at the root of your domain, such as https://example.com/robots.txt.

Block CloudflareCustomHostnameVerification from the whole site

User-agent: Cloudflare
Disallow: /

Block CloudflareCustomHostnameVerification from some folders

User-agent: Cloudflare
Disallow: /private/
Disallow: /search

Allow CloudflareCustomHostnameVerification only on some folders

User-agent: Cloudflare
Allow: /blog/
Disallow: /

Allow CloudflareCustomHostnameVerification and block other crawlers

User-agent: Cloudflare
Allow: /

User-agent: *
Disallow: /

Things to know

  • Each host needs its own file. Rules on www.example.com do not apply to shop.example.com.
  • A crawler obeys only the most specific group that names it. Once you add a User-agent: Cloudflare group, CloudflareCustomHostnameVerification ignores your User-agent: * rules, so repeat any that should still apply.
  • The user agent name is not case sensitive. We take Cloudflare from CloudflareCustomHostnameVerification's user agent; check the operator's own documentation if it publishes a different robots.txt name.
  • Crawlers cache robots.txt, so changes can take up to a day to apply. Disallow stops crawling but does not remove pages already collected or indexed.

Limits of robots.txt

  1. CloudflareCustomHostnameVerification may not follow the rule. robots.txt is a request that nothing enforces, and we have not confirmed that CloudflareCustomHostnameVerification follows it. Check your logs after adding a rule.
  2. The user agent could be fake. robots.txt matches the name a request claims. Anyone can send CloudflareCustomHostnameVerification's user agent, and a scraper using it is not bound by the operator's robots.txt policy. Only checking the source network tells a real CloudflareCustomHostnameVerification from a fake one.

Treat robots.txt as a statement of your policy, and enforce it where requests arrive.

Who should care about CloudflareCustomHostnameVerification

Publishers

CloudflareCustomHostnameVerification works for an SEO tool's customers, often your competitors. It adds server load without readers, so rate limit or block it unless you use the tool.

Transfon Security for publishers

Media buyers and advertisers

SEO crawlers map landing pages and links for competitor research. Keep CloudflareCustomHostnameVerification's visits out of campaign data.

Transfon Security for advertisers

E-commerce

CloudflareCustomHostnameVerification can map your catalogue, prices and site structure for competitors. Block it unless you use the tool yourself.

Transfon Security for e-commerce

SaaS and APIs

Allow CloudflareCustomHostnameVerification only if your team uses the tool; otherwise rate limit it on docs and marketing pages.

Transfon Security for SaaS and APIs

Block CloudflareCustomHostnameVerification with Transfon Security

robots.txt is a request, not an enforcement. Transfon Security shows CloudflareCustomHostnameVerification by name in the Top Bots report, so you can see how often it visits and which pages it reads. Block or allow it with a User Agent rule, or slow it down with a rate limit decision rule.

Transfon Security

Control CloudflareCustomHostnameVerification on your site

  • See every CloudflareCustomHostnameVerification visit and the pages it reads
  • Spot bots that fake trusted crawler names
  • Block, allow or rate limit CloudflareCustomHostnameVerification with one rule
  • Works with or without robots.txt support

Frequently asked questions

What is CloudflareCustomHostnameVerification?

CloudflareCustomHostnameVerification is a bot in the SEO crawlers category. Cloudflare Custom Hostname Verification service.

Does CloudflareCustomHostnameVerification respect robots.txt?

We have not confirmed whether CloudflareCustomHostnameVerification follows robots.txt. Add a robots.txt rule, then check your logs to see that it stopped, and block it by user agent if it did not.

How do I block CloudflareCustomHostnameVerification?

Add "User-agent: Cloudflare" followed by "Disallow: /" to the robots.txt file at the root of your site. To enforce it, block requests whose user agent contains "Cloudflare Custom Hostname Verification" at your WAF. In Transfon Security that is one User Agent block rule.

Is robots.txt enough to block CloudflareCustomHostnameVerification?

No. robots.txt is voluntary, so CloudflareCustomHostnameVerification may not follow it, and anyone can send CloudflareCustomHostnameVerification's user agent, so a fake CloudflareCustomHostnameVerification ignores your rule. Enforce the rule where requests arrive, at your WAF, and check the source network.

Should I block CloudflareCustomHostnameVerification?

SEO crawlers map links, keywords and technical issues for SEO tools and backlink databases. They help the tool's customers, often your competitors, rather than you. Rate limit or block the ones you do not use.

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