The ACF changes the way the IDL compiler interprets the interface definition, written in the IDL. The IDL file defines a means of interaction between a client and a server. For new server implementations to be compatible across the network with existing servers, the interaction between the client and server must not be modified. If the interaction between an application and a specific stub needs to change, you must provide an ACF when you build this stub.
The ACF affects only the interaction between the generated stub code and the local application code; it has no effect on the interaction between local and remote stubs. Therefore, client and server writers are likely to have different attribute configuration files that they can modify as desired.
More: