Article ID: 287058 - View products that this article applies to.
This article was previously published under Q287058
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In mixed-mode Exchange organizations that use certain routing configurations, messages may not be delivered if the least-cost route is "scoped" to the site level. When an address space on a connector is scoped to a site or a routing group, that particular address space (or route) is not known outside of the site or routing group.
For example, if an organization contains some Microsoft Exchange Server 5.5 sites that include a site (called SiteA) that has an Internet Mail Service with an SMTP:microsoft.com address space that is scoped to that site only, and the organization also contains other sites that have an Internet Mail Service with an SMTP:* address space, when a new Exchange 2000 server is installed in a different site in the organization and a user tries to send mail to firstname.lastname@example.org, a non-delivery report (NDR) and a 5.0.0 error are generated.
This problem can occur if the Exchange 2000 routing engine looks at all of the available routes (which include the route that is scoped to one site only) and determines that the best match for the message address is a route that is not available to the Exchange 2000 server (because it is in a different site or routing group) and returns "destination unreachable".
In Exchange Server 5.5, for the example in the "Symptoms" section of this article, the Gateway Address Routing Table (GWART) outside SiteA does not include the route. Servers in other sites simply use other connectors. Exchange 2000 should exclude the SiteA connector from the routing calculation and determine that an SMTP:* connector exists in another site. Customers who have satellite offices that do a lot of work with a particular partner may experience this problem.
To resolve this problem, obtain the latest service pack for Microsoft Exchange 2000 Server. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
(https://support.microsoft.com/kb/301378/EN-US/ )XGEN: How to Obtain the Latest Exchange 2000 Server Service Pack
To work around this problem for the routing configurations that are described in the "Symptoms" section of this article, locate the connector that has the scoped address space and add a more generic address space to that connector, so that the connector has both SMTP:* and SMTP:*@company.com address spaces.
Microsoft has confirmed that this is a problem in Microsoft Exchange 2000 Server. This problem was first corrected in Microsoft Exchange 2000 Server Service Pack 1.