Public Folder Replication Issue between Exchange 2003 and Exchange 2007

Recently, we have been seeing a number of issues where public folders cannot be replicated to Exchange 2007. The symptoms are:

1. Exchange 2007 Mailboxes are not able to view Exchange 2003 Public Folders through Outlook client.

2. On Exchange 2003 Server, the public folder replication messages are queued in the Messages with an unreachable destination queue.

3. On Exchange 2003 Server, you may find event below:

Event Type: Warning

Event Source: MSExchangeTransport

Event Category: Routing Engine/Service

Event ID: 951

Description:

When sending mail to the following address exchange2007name.domain.com.5B2DCAE3-0882-1148-8DEB-B36F641F9E2B, we have found the connector with target domain *.5B2DCAE3-0882-1148-8DEB-B36F641F9E2B matching destination address exists in DS. However, we have no way of getting there. You need to check your topology and add appropriate connectors among Routing Groups.

The root cause is that there is no Routing Group Connector between Exchange 2003 RG and Exchange 2007 RG. During Exchange 2007 installation, there is an option to select an Exchange 2000/2003 Routing Group Connector Bridge Head Server. If you do not configure this option, the Routing Group Connector won’t be created between the default routing group in Microsoft Exchange Server 2007 and Exchange Server 2003 routing groups.

Note: The first routing group connector between Exchange 2007 and Exchange 2003 or Exchange 2000 is created and configured during installation of the first Hub Transport Server role in an existing Exchange organization.

To resolve this issue, you can use the Exchange Management Shell to manually create the routing group connector.

For example, run the following command to create reciprocal routing group connectors between the Exchange 2007 routing group and the routing group that is associated with the specified Exchange Server 2003 server, assign a cost of 100 to that connector, and enable public folder referrals:

New-RoutingGroupConnector -Name "Interop RGC" -SourceTransportServers "Ex2007Hub1.contoso.com" -TargetTransportServers "Ex2003BH1.contoso.com" -Cost 100 -Bidirectional $true -PublicFolderReferralsEnabled $true