##### 3.2.2.4.7 DNS Change Confirming the Applicant's control over the FQDN by confirming the presence of a Random Value or Request Token for either in a DNS CNAME, TXT or CAA record for either 1) an Authorization Domain Name; or 2) an Authorization Domain Name that is prefixed with a Domain Label that begins with an underscore character. If a Random Value is used, the CA SHALL provide a Random Value unique to the Certificate request and SHALL not use the Random Value after i. 30 days or ii. if the Applicant submitted the Certificate request, the time frame permitted for reuse of validated information relevant to the Certificate (such as in [Section 4.2.1](#421-performing-identification-and-authentication-functions) of these Guidelines or Section 11.14.3 of the EV Guidelines). **Note**: Once the FQDN has been validated using this method, the CA MAY also issue Certificates for other FQDNs that end with all the Domain Labels of the validated FQDN. This method is suitable for validating Wildcard Domain Names.