The following paragraph from MSFT Best Practices for 2003 PKI says Windows 2000 authenticated via RPC vs 2003 that authenticates using DCOM
A CA running Windows Server 2003, Enterprise Edition, uses DCOM and Kerberos impersonation for authenticating requesters. It compares the client token against an access control list (ACL) set on the certificate template, as well as the DCOM enrollment interface on the CA itself, when a certificate is requested. A Windows 2000 Server CA uses remote procedure call (RPC) instead of DCOM to authenticate a requester. After the user is authenticated and authorized to gain access to the requested template, the CA can immediately process the request, as long as the user has the appropriate enrollment permissions on the template and if the CAs configuration is set to autoenroll.
Q: Can anyone explain how DCOM is different than RPC, in terms of Authentication and Authorization?
Some relevant screenshots of DCOM configuration (I don't have anything similar for RPC):
Why would software implementation choose DCOM over RPC? Is DCOM a superset of RPC or is it a separate entity?