Receiving the NTLM_NEGOTIATE IS Command

Expected AUTH_STATE: send_command_sent

An IS command with NTLM_CommandCode set to NTLM_NEGOTIATE indicates that the client has sent NTLM NEGOTIATE_MESSAGE.

On receiving this message, the server MUST call the appropriate local NTLM protocol function for processing the NTLM NEGOTIATE_MESSAGE.

If the NTLM NEGOTIATE_MESSAGE is a valid NTLM negotiate message, as specified in [MS-NLMP], the local NTLM protocol function returns an NTLM CHALLENGE_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.