Professional Windows® PowerShell for Exchange Server 2007 Service Pack 1

Part II: Working with Server Roles

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Figure 7-4

Finally, after successful delivery, the message is removed from the transport pipeline.

Please note that there are some Unified Messaging and Client Access instances that do not interact

directly with the transport pipeline. When a sent message is finally put in the outbox on behalf of the

sender, processing occurs by the same process as the submission process described previously.

To view the Hub Transport pipeline, use the

Get-TransportPipeline cmdlet as shown in

Figure 7 - 4 . The

TransportPipeline cmdlet also exposes two transport agents installed by default on

the Hub Trans port server: the Journaling Agent and the Transport Rule Agent. Agents are reviewed

in Chapter 9 .

Messages can enter the transport pipeline through any of four methods:

❑ Through an SMTP Receive Connector communicating on port 25.

❑ Through message files dropped into the Pickup or Replay directories.

❑ Through placement of messages in the Submission queue by the store driver.

❑ Through message submission via an agent.

In a nutshell, when a message is received by transport either through SMTP communication with

another mail host or dropped into the Pickup or Replay directories, it is placed in the Submission queue

to be picked up and processed by the Categorizer. The message recipients are resolved by the

Categorizer, the message ...