Pre-validation

Pre-validation methods help verify domain ownership before your customer's traffic is proxying through Cloudflare.

Use when

Use pre-validation methods when your customers cannot tolerate any downtime, which often occurs with production domains.

The downside is that these methods require an additional setup step for your customers. Especially if you already need them to add something to their domain for certificate validation, pre-validation might make their onboarding more complicated.

If your customers can tolerate a bit of downtime and you want their setup to be simpler, review our real-time validation methods.

How to

TXT records

TXT validation is when your customer adds a TXT record to their authoritative DNS to verify domain ownership.

Note

If your customer cannot update their authoritative DNS, you could also use HTTP validation.

To set up TXT validation:

1. When you create a custom hostname, save the ownership_verification information.

   {
   "result": [
       {
       "id": "3537a672-e4d8-4d89-aab9-26cb622918a1",
       "hostname": "app.example.com",
       // ...
       "status": "pending",
       "verification_errors": ["custom hostname does not CNAME to this zone."],
       "ownership_verification": {
           "type": "txt",
           "name": "_cf-custom-hostname.app.example.com",
           "value": "0e2d5a7f-1548-4f27-8c05-b577cb14f4ec"
       },
       "created_at": "2020-03-04T19:04:02.705068Z"
       }
   ]
   }

2. Have your customer add a TXT record with that name and value at their authoritative DNS provider.

3. After a few minutes, you will see the hostname status become Active in the UI.

4. Once you activate the custom hostname, your customer can remove the TXT record.

HTTP tokens

HTTP validation is when you or your customer places an HTTP token on their origin server to verify domain ownership.

To set up HTTP validation:

When you create a custom hostname using the API, Cloudflare provides an HTTP ownership_verification record in the response.

To get and use the ownership_verification record:

1. Make an API call to create a Custom Hostname.

2. In the response, copy the http_url and http_body from the ownership_verification_http object:

   Example response (truncated)

   {
     "result": [
       {
         "id": "24c8c68e-bec2-49b6-868e-f06373780630",
         "hostname": "app.example.com",
         // ...
         "ownership_verification_http": {
             "http_url": "http://app.example.com/.well-known/cf-custom-hostname-challenge/24c8c68e-bec2-49b6-868e-f06373780630",
             "http_body": "48b409f6-c886-406b-8cbc-0fbf59983555"
         },
         "created_at": "2020-03-04T20:06:04.117122Z"
       }
     ]
   }

3. Have your customer place the http_url and http_body on their origin web server.

   Example response (truncated)

   location "/.well-known/cf-custom-hostname-challenge/24c8c68e-bec2-49b6-868e-f06373780630" {
       return 200 "48b409f6-c886-406b-8cbc-0fbf59983555\n";
   }

   Cloudflare will access this token by sending GET requests to the http_url using User-Agent: Cloudflare Custom Hostname Verification.

   Note

   If you can serve these tokens on behalf of your customers, you can simplify their overall setup.

4. After a few minutes, you will see the hostname status become Active in the UI.

5. Once the hostname is active, your customer can remove the token from their origin server.