This figure depicts nine events through which an e-mail message passes where server-side rules can be triggered:

1. Composition by e-mail client and submission to system outbox.

2. Processing by the MTA.

3. Possible delivery to the Internet.

4. External messages arriving from the Internet through the MTA.

5. Messages for local delivery passed to system Inbox.

6. Delivery Agent processes system inbox.

7. Delivery agent passes message to a user's mailbox.

8. The user's client program reads and opens the message.

9. Eventually, the message is moved to the system Trash folder for final deletion.