Hub Transport Role Server

• Routing email inside the Active directory forest.

 * Hub-to-hub routing within an active directory forest uses Active directory sites, computing routes by using site link cost. Connections are created implicitly between Hub transport servers.

• Send connectors

 * creates a logical connection to a remote email system for the purpose of outbound transmission of email messages.

• Receiver Connectors

 * Server as a logical gateway through which all inbound messages are received. Receive connectors listen for inbound connections from other Hub and edge transport servers.

* Two are created by default: client, for SMTP connections from non-MAPI clients such as POP and IMAP, and default, for connections from other Hub and edge transport servers.

• Edge Subscriptions

 * Identifies the edge transport servers that will be managed through replicated configuration data from the Exchange Organization.

• Accepted Domains

 * Used to define which SMTP domains Exchange will accept for inbound email routing. These can be authoritative or relay domains.

• Remote Domains

 * SMTP domains which are external to your Exchange organization. They are used to define the settings for message transfer between your Exchange organization and domains outside your AD forest.