Queueing for Retransmission

If the mailer returns a "temporary failure" exit status, the message is queued. A control file describes the recipients and various other parameters. This control file is formatted as a series of lines, each describing a sender, a recipient, the time of submission, or some other parameter of the message. The header of the message is stored in the control file so that the associated data file in the queue is just the temporary file that was originally collected.