2.1 Transport
FRS is RPC-based, and both FRS interfaces MUST use the following protocol sequence:
NCACN_IP_TCP
By default, FRS replication over RPC occurs dynamically over an available port by using RPC endpoint mapper (also known as RPCSS) which is on port 135 (see [C706] part 4). This behavior can be overridden by a static port assignment so that FRS replication traffic passes through a specific port.
The protocol MUST use the underlying RPC protocol that is being used as a transport for FRS to retrieve the identity of the caller that made the method call.
FRS MUST have registered the following two security providers:<4>
RPC_C_AUTHN_GSS_KERBEROS
RPC_C_AUTHN_GSS_NEGOTIATE