3.2.5.1 Receiving a POP3_AUTH_NTLM_Initiation_Command Message
The expected state is start.
On receiving this message, the server MUST reply with the POP3_NTLM_Supported_Response, if it supports NTLM, and change its state to the inside_authentication state.
If the server does not support NTLM, it MUST respond with the POP3_AUTH_NTLM_Fail_Response, and change its internal state to completed_authentication.