2.7.1.5 Authentication Issues

Authentication is handled independently for each component protocol. Credential storage on Windows makes a distinction between session-based transports, such as RPC over SMB, and non-session-based transports, such as RPC over TCP/IP. If secondary credentials have been added by the user or another subsystem has been added to Credential Manager, these credentials are only used for protocol requests by using session-based transport. They are unavailable for non-session based transports.

Specifically, that means that requests over the Print System Asynchronous protocols [MS-PAR] [MS-PAN] can fail due to failed authentication, even if requests over the Print System Remote Protocol [MS-RPRN] operate correctly. Print client architecture is designed to handle these failures gracefully and to fall back to using the Print System Remote Protocol if the Print System Asynchronous protocols fail due to authentication issues. Therefore, functionality that is specific to the Print System Asynchronous protocols can be unavailable in such a fallback scenario.