3.2.5.1.2.1 NTLM Returns Success, Returning an NTLM Message

If the server passes an NEGOTIATE_MESSAGE NTLM message to the NTLM subsystem, the NTLM subsystem returns an NTLM CHALLENGE_MESSAGE message. The server encapsulates the CHALLENGE_MESSAGE message in an IMAP4_AUTHENTICATE_NTLM_Blob_Response message and sends it to the client. The server does not change its internal state.