Domain Validation SSL certificates are the most basic of the three types of SSL/TLS certificates. While Organization Validation and Extended Validation require multiple steps in which the Certificate Authority vets the company or organization applying for the certificate, Domain Validation takes just a single step. The Certificate Authority must simply verify that the person or organization applying for the certificate owns the registered domain.

What is Domain Validation?

To satisfy the Domain Validation requirement you must prove you own the domain that was submitted with the order.

The easiest, and most preferred method for accomplishing this is via email-based authentication. 

During email-based authentication, the the CA will send a domain approval email to one of five pre-approved email addresses associated with the website. Please note that any email address not on the pre-approved address list will not be usable for domain control verification. 

The five pre-approved addresses are:

• [email protected]
• [email protected]
• [email protected]
• [email protected]
• [email protected]

If you cannot satisfy the Domain Validation requirement via email, there are alternative methods as well.

Alternative Methods

There are two additional ways to satisfy the Domain Validation requirement if email does not work for you. The specific instructions and values/files required are provided to you after generating your SSL order.

• File-Based Authentication – The CA will provide you with a text file that you will need to upload to the root directory of your website. This will then be verified by the CA via HTTP or HTTPS.
• DNS-Based Authentication  – The CA will provide you with two unique hash values. You, in turn, must create a DNS record on your domain with these values to complete validation. 

Now all that's left is for the CA to issue you the SSL certificate, then you'll need to install it.