Detecting Sequence Problems in GSS-API

As a context initiator transmits sequential data packets to the acceptor, some mechanisms allow the context acceptor to check for proper sequencing. These checks include whether the packets arrive in the right order, and with no unwanted duplication of packets. See following figure. An acceptor checks for these two conditions during the verification of a packet and the unwrapping of a packet. See Unwrapping the Message for more information.

Figure 4–8 Message Replay and Message Out-of-Sequence

With gss_init_sec_context(), an initiator can check the sequence by applying logical OR to the req_flags argument with either GSS_C_REPLAY_FLAG or GSS_C_SEQUENCE_FLAG.