3.1.1.1 IMAP4 NTLM Extension State Model

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 The following figure shows the client IMAP4 NTLM extension state model.

Client IMAP4 NTLM state model

Figure 1: Client IMAP4 NTLM state model

The abstract data model for IMAP4 NTLM extension has the following states:

  1. Start: State of the client before the IMAP4_AUTHENTICATE_NTLM_Initiation_Command message has been sent.

  2. sent_authentication_request: State of the client after the IMAP4_AUTHENTICATE_NTLM_Initiation_Command message has been sent.

  3. inside_authentication: State that is entered by a client after it has received an IMAP4_AUTHENTICATE_NTLM_Supported_Response message. In this state, the client initializes the NTLM subsystem and performs the following steps:

    • Encapsulates the NTLM message, returned by the NTLM subsystem, into an IMAP4_AUTHENTICATE_NTLM_Blob_Command message and sends the message to the server. Waits for a response from the server.

    • De-encapsulates the received IMAP4_AUTHENTICATE_NTLM_Blob_Response message data (if any) from the server and converts it to NTLM message data.

    • Passes the NTLM message data to the NTLM subsystem.

    • Encapsulates the NTLM authenticate message, returned by the NTLM subsystem, into an IMAP4_AUTHENTICATE_NTLM_Blob_Command message.

    • Sends the IMAP4_AUTHENTICATE_NTLM_Blob_Command message to the server.

      The inside_authentication state terminates when:

    • An IMAP4_AUTHENTICATE_NTLM_Succeeded_Response, IMAP4_AUTHENTICATE_NTLM_Fail_Response, or IMAP4_AUTHENTICATE_NTLM_Cancelled_Response message is received.

    • Any failure is reported by the NTLM subsystem.

  4. completed_authentication: State of the client on exiting the inside_authentication or the sent_authentication_request state. The rules for exiting the inside_authentication state are defined in section 3.1.5.1.4 and section 3.1.5.1.5. The behavior of IMAP4 in this state is outside the scope of this specification.