As I mentioned earlier, this is a stand-alone root CA, and it is not part of the domain. However, CRL Distribution Points (CDP) and authority information access (AIA) locations, which are required by the CA, will be stored in DC. Since they use DN names with a domain, the root CA needs to be aware of the domain information to publish it properly. It will retrieve this information via a registry key:

certutil.exe –setreg caDSConfigDN CN=Configuration,DC=rebeladmin,DC=com