code: func (l *arpaReservedIP) CheckApplies(c *x509.Certificate) bool {
  	names := append([]string{c.Subject.CommonName}, c.DNSNames...)
  	for _, name := range names {
  		name = strings.ToLower(name)
  		if strings.HasSuffix(name, rdnsIPv4Suffix) ||
  			strings.HasSuffix(name, rdnsIPv6Suffix) {
  			return true
  		}
  	}
  	return false
  }
docs: // CheckApplies returns true if the certificate contains any names that end in
  // one of the two designated zones for reverse DNS: in-addr.arpa or ip6.arpa.