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Overview of the Processing Flow of Inbound Email Messages

When the Internet SMTP/POP3 Server driver or Internet SMTP/IMAP Server driver starts, it creates required directories, such as a directory for incoming email. The driver also creates a thread that polls the POP3 or IMAP server. The PollingInterval driver parameter controls the frequency with which the driver checks the POP3 or IMAP server for messages.

If messages exist for the POP3 server, then the driver retrieves and processes them one at a time, up to a maximum for each session equal to the value in the POP3 Batch Size driver parameter. If the current session with the POP3 server terminates abnormally, then all messages previously retrieved, processed, and deleted during the current session are restored, retrieved, and processed again the next time that the driver connects to the POP3 server. The smaller the value of the driver parameter, the fewer duplicate messages are created and processed if a restart occurs.

Messages in a session are processed as shown in the following steps:

1. A retrieve command downloads and saves a message to the directory for incoming email.

   For the POP3 server, the retrieve command is POP3 RETR. The name of the temporary file for the message is POP3_A_B_C_D_E_F.tmp. For more information about the files that the processing flow creates, see Attachments Created When Inbound Email Is Received.

2. A delete command deletes the message from the POP3 or IMAP server.

   For the POP3 server, the delete command is POP3 DELE. If the delete command fails, then the message that is stored in the directory for incoming email is erased because it is retrieved again in the next POP3 or IMAP session.

   NOTE:  Do not set up other email clients to access the mailboxes that Siebel Email Response monitors because the email driver deletes the messages from the POP3 or IMAP server when Siebel Email Response processes them. These deleted messages are not visible to another client.

3. The disk-based message is parsed. The parsing produces the following files in the directory for incoming email:
   1. OriginalMessageText_A_B_C_D_E_F_G.txt.
   2. Any attachments parsed from message are given unique names as follows: ATT_A_B_C_D_E_F_G.dat.
   3. Any remaining text or HTML fragments are converted to attachments and are given unique names as follows: ATT_A_B_C_D_E_F_G.dat.

      CAUTION:  Any errors that occur in the workflows can place the ATT_A_B_C_D_E_F_G.dat files in the directory for incoming email. If this placement occurs when the Communications Inbound Receiver is not running, then the workflow that the Communications Inbound Receiver invokes fails to process a message event.

      To determine if you can delete an ATT_A_B_C_D_E_F_G.dat file in the directory for incoming email, stop the Communications Inbound Receiver, and then look at the contents of all the queued Communications Inbound Receiver events in all response groups to make sure that the ATT_A_B_C_D_E_F_G.dat files are no longer referenced.

4. If an error occurs when the message is parsed, then the following events occur:
   1. The temporary file is moved to the directory for failed email and any created attachments are deleted.
   2. The POP3 or IMAP session is immediately terminated with a quit command so that the error message is permanently deleted from the server.
5. If the Loopback Detection Interval parameter value is greater than zero, and the message sender is currently blocked, then the following events occur:
   • If the Process If Loopback Detected parameter value is False, then the message is moved to the directory for loopback email.
   • If the Process If Loopback Detected parameter value is True, then the driver's Loopback Candidate flag is set to True, and the message continues processing.
6. If the message is not moved to the directory for loopback email or flagged as a loopback candidate, then the temporary file is processed as follows:
   • If the Delete Processed Messages parameter value is True, then the temporary file is deleted.
   • If the Delete Processed Messages parameter value is False, then the temporary file is moved to the directory for processed email.
7. The primary message text, header information (subject, to, cc, date, and so on), Loopback Candidate flag, and references to the attachments are passed to the driver's creator (usually Communications Inbound Receiver).
8. The Internet SMTP/POP3 Server driver or Internet SMTP/IMAP Server driver does not delete the OriginalMessageText file and all the attachments. The workflow that the Communications Inbound Receiver invokes deletes all the attachments.