Applies to: Exchange Server 2010 SP3, Exchange Server 2010 SP2

Topic Last Modified: 2011-04-28

In Microsoft Exchange Server 2010, the transport pipeline is a collection of Exchange 2010 server roles, connections, components, and queues that work together to route all messages to the categorizer on a Hub Transport server inside the organization. Messages from outside the organization enter the transport pipeline through a Receive connector on an Edge Transport server and are then routed to a Hub Transport server inside the organization. Messages inside the organization enter the transport pipeline on a Hub Transport server in one of the following ways:

Every message that's sent or received by an Exchange 2010 client must be categorized on a Hub Transport server before it can be routed and delivered. After a message has been categorized, it's put in a delivery queue for delivery to a mailbox in the same Active Directory site as the Hub Transport server on which the message was categorized or for routing to a recipient in a different Active Directory site or forest, or to a recipient outside the organization.

The Exchange 2010 transport pipeline consists of the following components and processes:

The following figure shows the relationships among the components in the Exchange 2010 transport pipeline.

Transport pipeline overview diagram

Looking for management tasks related to managing transport servers? See Managing Transport Servers.