More domain security with CAA records
Domain owners are now able to specify which certificate authorities (CA) are allowed to issue SSL/TLS-certificates for their domains. This CAA record (Certification Authority Authorization) adds an additional layer of security to your domain, and avoids mis-issuing of certificates e.g. in case of man-in-the-middle attacks.
To add or change a CAA record for one of your domains, please visit the DNS configuration of that domain and chose "CAA Record" in the section "Edit records/Create new record".
To find out more about DNS and CAA, you may also have a look at Wikipedia.