When you plan for a period of coexistence with Exchange 2007 and
Exchange Server 2003 or Exchange 2000 Server, you must understand the differences in how each version determines its routing topology.
Exchange Server 2003 and Exchange 2000 Server use routing groups to define an Exchange-specific routing topology. Typically, routing groups are used to specify a set of well-connected Exchange servers. Servers in the same routing group can communicate with each other without the use of connectors. Ideally, the routing groups that are defined in your existing environment are based on IP subnets and closely mirror the Active Directory Site configuration. When more than one routing group is defined in an Exchange Server 2003 organization, the administrator must manually create routing group connectors to enable mail flow between Exchange Server 2003 servers that are in different routing groups. The routing group connector must specify a source server and a target server as the connector end points. A routing group connector defines a one-way connection, and a reciprocal connector
must be created to establish mail flow in both directions. The source and target servers are the bridgehead servers for the routing group. The bridgehead servers relay e-mail to other routing groups on behalf of other servers in their routing group and receive e-mail from other routing groups for delivery to other servers in their routing group. Every Exchange 2003 or Exchange 2000 routing group should have at least one connector to another routing
group before you introduce the first Exchange 2007 server. Event ID 5006 is logged for each Microsoft Exchange Message Database (MDB) that is located in a routing group that does not have a routing group connector path from the Exchange 2007 routing group. For more information about the Exchange Server 2003 routing topology, s
Exchange 2007 uses the existing Active Directory site topology to define its routing topology. Servers that are located in the same Active Directory site can communicate without the use of connectors. E-mail that is routed to Exchange servers that are located in different sites must be relayed by Hub Transport servers. Hub Transport servers send e-mail to Hub Transport servers in remote sites by using the intra-organization Send connector. The intra- organization Send connector is an implicit connector that is computed by using
Active Directory site and IP site link information. In Exchange 2007, an administrator no longer has to define an Exchange-specific routing configuration. However, an administrator can make Exchange-specific configuration changes to Active Directory sites and IP site link costs to control mail flow.
To support coexistence between these two routing topologies, all Exchange 2007 servers are automatically added to a single routing group when Exchange 2007 is installed. The
Exchange 2007 routing group is recognized in Exchange System Manager in Exchange Server 2003 or Exchange 2000 Server as Exchange Routing Group
(DWBGZMFD01QNBJR) within Exchange Administrative Group (FYDIBOHF23SPDLT). When the first Exchange 2007 Hub Transport server is installed in an existing Exchange organization, you must specify an Exchange 2003 bridgehead server to which to establish the first routing group connector. We recommend that you select a bridgehead server that is located in a hub routing group or in a routing group that has many mailboxes. The routing group connector links the routing group where the Exchange 2003 server resides and the Exchange 2007 routing group. The Exchange 2007 routing group includes all Exchange 2007 servers, regardless of the Active Directory site in which they reside.
Caution:
Do not move Exchange 2007 servers out of Exchange Routing Group (DWBGZMFD01QNBJR) and do not rename Exchange Routing Group
(DWBGZMFD01QNBJR) by using a low-level directory editor. Exchange 2007 must use this routing group for communication with earlier versions of Exchange. We do not support moving Exchange 2007 servers out of Exchange Routing Group (DWBGZMFD01QNBJR) or renaming of Exchange Routing Group
The Hub Transport server that you are installing and the Exchange 2003 bridgehead that you select are configured as the source and target servers on two reciprocal routing group connectors. The selected bridgehead server is automatically added to the membership of the ExchangeLegacyInterop universal security group and is granted the permissions that are needed to send e-mail to and receive e-mail from Exchange 2007. This routing group connector creates a single connection point between Exchange 2003 and Exchange 2007. The bridgehead server that you select depends on your current routing environment. You can modify the list of source and target servers by using the Set-RoutingGroupConnector
If your existing Exchange environment includes more than one routing group, you may want to create additional connection points between Exchange 2003 and Exchange 2007 to optimize mail flow. To create additional connection points, you follow these steps: cmdlet in the Exchange Management Shell. It is a best practice to specify more than one source server and more than one target server to provide redundancy and server availability.
• Determine how you will transition the organization to Exchange 2007. The order in which you decommission routing groups will determine which Exchange 2003 routing groups should connect directly with Exchange 2007.
• Modify the registry to suppress minor link state updates on all the Exchange 2003 and Exchange 2000 servers. This configuration change prevents connector state messages from being relayed throughout the organization by using link state updates, but does not prevent configuration change messages from being relayed. For more information, see
• Use the New-RoutingGroupConnector cmdlet in the Exchange Management Shell to create all routing group connectors that specify Exchange 2007 Hub Transport servers as source or target servers. Configure a routing group connector from the Exchange Routing Group (DWBGZMFD01QNBJR) to each Exchange Server 2003 or
Exchange 2000 Server routing group with which Exchange 2007 will communicate directly, and configure the corresponding reciprocal routing group connectors. You can use the Bidirectional parameter with the New-RoutingGroupConnector cmdlet to create both connectors in a single operation. These connectors will enable mail flow between Exchange Server 2003 or Exchange 2000 Server and Exchange 2007, and
from Exchange 2007 to Exchange Server 2003 or Exchange 2000 Server. You must use the Exchange Management Shell cmdlets to create and configure routing group
connectors between Exchange 2007 and earlier versions of Exchange. When you use the Exchange 2007 tools, the specified legacy Exchange servers are automatically added to the membership of the ExchangeLegacyInterop universal security group and the permissions that are required to allow a legacy Exchange server to send mail to and receive mail from an Exchange 2007 Hub Transport server are automatically granted. If you use Exchange System Manager to create a routing group connector between the Exchange 2007 routing group and any Exchange 2003 or Exchange 2000 routing group, this group membership is not updated correctly and the connector will not work correctly.
Important:
Placing Exchange 2007 servers and Exchange 2003 or Exchange 2000 servers in the same routing group is not supported.
Important:
If you deploy Exchange 2007 as a new organization, you cannot later install Exchange 2003 or Exchange 2000 in the Exchange 2007 organization. This is not a supported scenario. If you anticipate requiring Exchange 2003 functionality in your organization in the future, you must first install an Exchange 2003 organization and maintain at least one Exchange 2003 server.
For more information about how Exchange 2007 determines its routing topology, see Planning to Use Active Directory Sites for Routing Mail. For more information about the differences in routing behavior between Exchange 2007 and earlier versions of
Exchange Server, see