18.104.22.168.1 Receiving the NTLM_NEGOTIATE IS Command
Expected AUTH_STATE: send_command_sent
On receiving this message, the server MUST call the appropriate local NTLM protocol function for processing the NTLM NEGOTIATE_MESSAGE.
The local NTLM protocol implementation returns a failure error code if the NTLM NEGOTIATE_MESSAGE is not valid. The server's response must depend on the error code returned by the local NTLM software.
Neither the mechanism for returning the NTLM CHALLENGE_MESSAGE nor the mechanism for returning a failure error code is defined by the Telnet: NTLM Authentication Protocol. These mechanisms are defined by the implementation of the NTLM protocol in use on the client.