Applies to: Exchange Server 2007 SP3, Exchange Server 2007 SP2, Exchange Server 2007 SP1, Exchange Server 2007
Topic Last Modified: 2009-09-02

A connector is a logical representation of a connection between a source server and a destination server. The connectors describe how computers that are running Microsoft Exchange Server 2007 and that have Edge Transport server role or Hub Transport server role installed communicate:

Connectors are classified as Send connectors, Receive connectors, or Foreign connectors. All Send connectors and Receive connectors use the Simple Mail Transfer Protocol (SMTP) to transport messages. In contrast, Foreign connectors transport messages from Hub Transport servers to local messaging servers that do not use SMTP to transport messages. All Receive connectors accept mail only from SMTP address spaces. However, Send connectors and Foreign connectors may be configured to send mail to SMTP or non-SMTP address spaces, such as X.400..

This topic provides information about the connectors used in Exchange 2007 and the tasks that you perform to manage them.

Receive Connectors

Receive connectors represent an inbound connection point for SMTP. A Receive connector defines how inbound SMTP communications are handled on an Exchange 2007 transport server. In Exchange 2007, the Receive connector is a "receive listener." This means that the connector is listening for inbound connections that match the settings of the Receive connector. A Receive connector listens for connections that are received through a particular IP address and port and from a specified IP range.

You can also configure a Receive connector by configuring limits such as the number of active connections, maximum message size, and maximum recipients per message that will be accepted by the connector.

Receive connectors are scoped to a single server and determine how that specific server listens for connections. When you create a Receive connector on a Hub Transport server, the Receive connector is stored in the Active Directory directory service as a child object of the server on which it is created. When you create a Receive connector on an Edge Transport server, the Receive connector is stored in Active Directory Application Mode (ADAM).

Send Connectors

Send connectors relay outbound communications. You set one or more source servers on a Send connector. The source servers are the transport servers that are associated with that connector to handle message delivery. When an Exchange 2007 server receives messages for a remote destination, they are relayed to the source server of a Send connector that is configured to send e-mail to the destination domain. Send connectors are not scoped to a single server. In Active Directory or in ADAM, a Send connector is created as an object in a connectors container.

Foreign Connectors

Foreign connectors use the Drop directory on a Hub Transport server to send messages to a local messaging server that doesn't use SMTP as its primary transport mechanism. These messaging servers are known as foreign gateway servers. Third-party fax gateway servers are examples of foreign gateway servers. The address spaces that are assigned to a Foreign connector can be SMTP or non-SMTP. For more information, see the following topics:

How Connectors are Created

Connectors can be created explicitly, implicitly, or automatically.

  • A connector is created explicitly by the administrator.

  • A connector is created implicitly when it is computed from the system topology. In this case it is not displayed in the Exchange Management Console or by using tasks in the Exchange Management Shell.

  • Connectors are created automatically by using the Edge Subscription process and during setup.

You don't have to configure connectors between the Hub Transport servers inside the Active Directory forest. In the Exchange 2007 organization, connections between Hub Transport servers are created implicitly by computing a path between Active Directory sites that is based on Active Directory Site Link Cost.

The connectors that establish mail flow to the Internet are created automatically when you subscribe an Edge Transport server to the Exchange organization. After you install the Edge Transport server role and the Hub Transport server role, you subscribe the Edge Transport server to an Active Directory site by using the Edge Subscription process. During this process, data that is stored in Active Directory is replicated to the ADAM instance on the Edge Transport server to enable end-to-end mail flow. This data includes the configuration of Send connectors and accepted domains. We recommend that you subscribe the Edge Transport server to an Active Directory site to provision the connectors between the Exchange organization and the perimeter network and between the perimeter network and the Internet.

If you want to create a unique connector configuration for an external domain, you can use the tasks in the Exchange Management Console and in the Exchange Management Shell.

Connector Management Tasks

You can use the Exchange Management Console or the Exchange Management Shell to manage connectors. Some of the configuration options for connectors are available only in the Exchange Management Shell. Typical connector management tasks include the following:

  • Create a new connector.

  • Delete a connector.

  • Enable or disable a Send connector.

  • Configure a smart host on a Send connector.

  • Configure permissions on Receive connectors.

  • Establish message size limits.

  • Set protocol logging level.

  • Configure supported authentication mechanisms.

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