Microsoft Certificate Services allows you to issue and revoke digital certificates. You can use these certificates to enable SSL sessions and to authenticate the identity of your intranet, extranet, or Internet Web site.
Certificate Services is a Windows service that runs on a designated certificate server. Certificate servers can be configured as one of four types of CAs:
Enterprise root CA. The certificate server at the root of the hierarchy for a Windows domain. It’s the most trusted CA in the enterprise and must be a member of the Active Directory service and have access to it.
Enterprise subordinate CA. A certificate server that will be a member of an existing CA hierarchy. ...