Mail Flow — overview

Outbound flow

After Send, DES validates identity and policy, records the request in outbox or the flow queue, and a worker claims it for delivery. Subsequent states show queued, claimed, processing, sent, retry or failed.

Inbound flow

SMTP/LMTP or an Edge component accepts the message, submits it to security and policy processing, then stores it in the target mailbox or routes it to Spam or Quarantine.

Admin → Flow

The screen summarises domains, outbox records and queue items. An operator can open a record, inspect the error reason and, when safe, requeue it or mark it failed.

Important principle

The HTTP response from Compose is not proof of final external delivery. Use Message Trace and final queue state. For inbound mail, also review security decision, folder placement and recipient.