The Certification Authority Authorization (CAA) DNS Resource Record allows a DNS domain name holder to specify one or more Certification Authorities (CAs) authorized to issue certificates for that domain.
CAA Resource Records allow a public Certification Authority to implement additional controls to reduce the risk of unintended certificate mis-issue.
This document defines the syntax of the CAA record and rules for processing CAA records by certificate issuers.
https://tools.ietf.org/html/rfc6844