Troubleshoot Mail Routing Problems


Topic Last Modified: 2007-02-08

Microsoft® Exchange Server 2003 maintains routing information in the Active Directory® directory service configuration naming context. You configure the routing information by means of the address spaces and cost factors that you assign to the individual connector instances in Exchange System Manager. Address spaces are subsets of e-mail address information that are used to categorize recipients. An example of a Notes address space is NOTES:*@*.

You can also assign more detailed address spaces, such as NOTES:*@Contoso, which is useful if you want to distribute the message traffic over multiple connector instances. Generally, the Exchange transport engine chooses more detailed address spaces over general address spaces. However, it is recommended that you assign the most general address space possible to include all possible recipients in the same address space. For example, you should configure NOTES:*@* if you are using only one Exchange Connector for Lotus Notes instance to connect your entire Exchange Server 2003 organization to a global Lotus Notes/Domino environment.

You can use the WinRoute tool to view message routes and connector states when you are troubleshooting problems related to message routing in an Exchange Server 2003 organization. The WinRoute tool extracts link state information from Exchange Server 2003 and presents the information in a readable format. For more information, including a link to download the tool, see Exchange Server WinRoute.

If the routing module cannot match a recipient address to a connector address space, a non-delivery report (NDR) is generated. This report indicates that the recipient name could not be resolved. The numerical error code will be either 5.0.0 (There is no route) or 5.4.0 (Host not found in DNS). For more information about the information contained in NDRs, see Microsoft Knowledge Base article 284204, "Delivery status notifications in Exchange Server and in Small Business Server."

If a Lotus Notes user tries to Reply to All to a message from an Exchange user, NDRs will be generated if directory synchronization is not installed and configured or if recipients are not listed in the Directory (for example, mail routing to Internet e-mail addresses). This problem can be resolved by adding NoOptimizeLocalRouting=1 to the Notes client's Notes.ini file.

Microsoft does not support backboning Exchange Server messaging systems via Lotus Domino. Microsoft defines backboning as having two or more Exchange Server messaging systems in different forests connected via a single or multiple Lotus Domino servers or domains.