Rewrite Host headers

Customers can rewrite Host headers using different Cloudflare rules. This feature is currently available for domains on the Enterprise plan.

Warning

Consider alternative Rules options due to their enhanced configurability. Refer to the migration guide for details.

For more flexibility and customization, consider using Snippets.

A common use case for this functionality is when your content is hosted on an Amazon S3 bucket. Amazon has designed their system to only accept host headers that have the same name as the bucket hosting your content. In this way, a request to Host: your-domain.com must be rewritten to Host: your-bucket.s3.amazonaws.com, or else the request will be denied.

In some cases, you can adjust your Amazon S3 Bucket to accept Host headers that are not the bucket name.

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To rewrite the Host header:

1. Log in to your Cloudflare account ↗, and select your account and domain.
2. Go to Rules > Page Rules.
3. Select Create Page Rule.
4. Specify the URL to match.
5. In Pick a Setting, select Host Header Override. Then, enter the override value.
6. Select Save and Deploy Page Rule.

Now, any request matching the URL you specified will have the Host header overridden to the one you entered in the Host Header Override text box.

Warning

Page Rules require a proxied DNS record to work. Page Rules will not apply to subdomains that do not exist in DNS or are not being directed to Cloudflare.