Alternative Methods of Domain Control Validation (DCV)
Posted by Leonard Grove on 14 December 2011 03:13 PM
All SSL.com certificates must pass through DCV (Domain Control Validation) before they are issued. DCV is a mechanism used to prove ownership or control of a registered domain name.
There are 3 mechanisms for DCV:
- eMail-based DCV (Traditional)
You will be sent an email to an administrative contact for your domain. The email will contain a unique validation code and link. Clicking the link and entering the code will prove domain control.
- DNS CNAME-based
This method requires you to create a CNAME entry in your domain’s DNS record that is pointed at comodoca.com. An MD5 hash as well as a SHA-256 hash of the CSR are required for this CNAME entry. The CNAME entry should follow this formula:
_<MD5 hash>.<domain> <TTL> IN CNAME <SHA-256 hash>.comodo.com
Please notice the underscore at the beginning of the entry, which is required. Additionally, because the SHA-256 hash is 64 characters long, it will need to be split into two 32-character subdomains.
- HTTP-based DCV
The CSR you submit to SSL.com will be hashed. The hash values are provided to you and you must create a simple plain-text file and place this in the root of your webserver and served over HTTP-only!
The file and it's content should be as follows:
http://yourdomain.com/.well-known/pki-validation/<Upper case MD5 hash of CSR>.txt
Content (as a plain text file):
<SHA1 hash of CSR>
Note: Serving the page over HTTPS or using an HTTP 302 redirect to an HTTPS will cause a failure of verification. Please use HTTP only for this procedure!
CSR hashes are provided to you once you submit the CSR as part of the ordering process.