3.3.5 Message Processing Events and Sequencing Rules

Message processing in the DRS Protocol Extensions for SMTP begins when the SMTP Mail Transfer Agent (MTA) delivers an SMTP message to the server process for the DRS Protocol Extensions for SMTP. This operation MUST validate the frame that is received from the SMTP Mail Transfer Agent (MTA), decode the frame into its constituent fields, and pass the resulting DRS data to the DRS Remote Protocol layer.