Forcing Exchange to route internal emails through SMTP Connector

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How to Configure Exchange to Forward Messages to a Foreign Messaging System That Shares the Same SMTP Domain Name Space
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This article was previously published under Q319759
SUMMARY
This article describes how to configure Microsoft Exchange to send messages to contacts whose user accounts exist in Active Directory, but whose e-mail addresses point to a foreign messaging system that shares the same SMTP domain name space as the Exchange server.

By default, if a group of e-mail recipients in an Exchange message handling system and a group of recipients in a foreign e-mail system (UNIX SendMail, for example) share the same Simple Mail Transfer Protocol (SMTP) domain, e-mail does not flow from Exchange to the foreign recipients. Exchange generates non-delivery reports (NDRs).
MORE INFORMATION
For additional information, click the article number below to view the article in the Microsoft Knowledge Base:
321721 XCON: Sharing SMTP Address Spaces in Exchange 2000
To configure Exchange to forward messages to a foreign messaging system that shares the same SMTP domain name space, follow these steps.

Note The domain name of Example.com is used throughout these steps as an example.
1.      Modify the Exchange default recipient policy to have a single primary SMTP address of @local that is authoritative. Create a secondary SMTP address that points to your domain name space. To do this, follow these steps:
1.      Start Exchange System Manager. To do this, click Start, point to Microsoft Exchange, and then click System Manager.
2.      Under Your Organization (Exchange), expand Recipients, click Recipient Policies, and then double-click Default Policy in the right pane of Exchange System Manager.
3.      Click the E-Mail Addresses tab, click the SMTP address (but do not click to clear the check box), and then click Edit.
4.      In the Address box, type @local.
5.      Click to select the This Exchange Organization is responsible for all mail delivery to this address check box (if it is not already selected), and then click OK.
6.      Click New, click SMTP Address, and then click OK.
7.      In the Address box, type @example.com (where example.com is the name of your SMTP domain name space).
8.      Click to clear the This Exchange Organization is responsible for all mail delivery to this address check box, and then click OK.
9.      Click the SMTP item that corresponds to the @local address space, and then click Set as Primary if the button is available (does not appear dimmed).
10.      Click OK, and then click Yes when you are prompted to update all corresponding recipient e-mail addresses.
2.      Create a second, higher-priority recipient policy with the Primary SMTP address that points to your domain name space and a secondary authoritative SMTP address of @local. To do this, follow these steps:
1.      In Exchange System Manager, right-click Recipient Policies, point to New, and then click Recipient Policy.
2.      Select the E-Mail Addresses check box, and then click OK.
3.      Type a friendly name for the policy in the Name box, and then click the Modify.
4.      In the Find list, click Exchange Recipients, and then click OK.
5.      Click OK, and then click the E-Mail Addresses (Policy) tab.
6.      Click the SMTP item that corresponds to your domain name space. For example, click @example.com, and then click Set as Primary.
7.      Click the SMTP item that corresponds to your domain name space (for example, click @example.com), and then click Edit.
8.      Click to clear the This Exchange Organization is responsible for all mail delivery to this address check box (if it is not already cleared), and then click OK.
9.      Click @local, and then click Edit.
10.      Click to select the This Exchange Organization is responsible for all mail delivery to this address check box (if it is not already selected), and then click OK.
11.      Click Apply, click Yes to update all corresponding recipient e-mail addresses, click Yes to update all corresponding recipient e-mail addresses after the addresses of type [smtp] have been modified, and then click OK.

The new policy is displayed above Default Policy in the right pane of Exchange System Manager.
3.      Modify the default SMTP Virtual Server properties to remove message forwarding for unresolved recipients. To do this, follow these steps:
1.      In Exchange System Manager, expand Administrative Groups, expand First Administrative Group, expand Servers, expand ServerName, expand Protocols, expand SMTP, and then click Default SMTP Virtual Server.

NOTE: You may have to expand SMTP Virtual Servers before you can click Default SMTP Virtual Server item.
2.      Right-click Default SMTP Virtual Server, and then click Properties.
3.      Click the Messages tab.
4.      Remove any entries that are displayed in the Forward all mail with unresolved recipients to host box, and then click OK.
4.      Create an SMTP connector that forwards all messages to the foreign messaging system. To do this, follow these steps:
1.      In Exchange System Manager, expand Administrative Groups, expand First Administrative Group, right-click Connectors, point to New, and then click SMTP Connector.
2.      In the Name box, type a descriptive name for this connector.
3.      Click Forward all mail through this connector to the following smart hosts, and then type the IP address of the remote messaging system inside square brackets ([]). For example, type:
[192.168.1.100]
4.      Click Add, click Default SMTP Virtual Server in the SMTP virtual server instances list, and then click OK.
5.      Click the Address Space tab, and then click Add.
6.      Click SMTP, and then click OK.
7.      In the E-mail domain box, type your e-mail domain. Do not precede the e-mail domain with the at sign (@). For example, type example.com.
8.      Click OK.
9.      Click to select the Allow messages to be relayed to these domains check box, and then click OK.
5.      Restart the Routing and SMTP services. To do this, follow these steps:
1.      Click Start, click Run, type services.msc, and then click OK.
2.      Right-click Microsoft Exchange Routing Engine, and then click Stop.
3.      Right-click Microsoft Exchange Routing Engine, and then click Start.
4.      Right-click Simple Mail Transport Protocol (SMTP), and then click Stop.
5.      Right-click Simple Mail Transport Protocol (SMTP), and then click Start.
6.      Quit the Services snap-in.
6.      Rebuild the Recipient Update Service (RUS). To do this, follow these steps:
1.      In Exchange System Manager, expand Recipients, and then click Recipient Update Services.
2.      In the right pane of Exchange System Manager, right-click the Recipient Update Service item (not the Enterprise Configuration item), and then click Rebuild.
3.      Click Yes to confirm the rebuilding of the client addresses.
4.      Quit Exchange System Manager.
7.      Create a new contact with an e-mail address, and then test the Exchange configuration.
The information in this article applies to:
"      Microsoft Exchange Server 2003 Enterprise Edition
"      Microsoft Exchange Server 2003 Standard Edition
"      Microsoft Exchange 2000 Server
"      Microsoft Windows Small Business Server 2003, Premium Edition
"      Microsoft Windows Small Business Server 2003, Standard Edition
Last Reviewed:      10/9/2003 (4.0)
Keywords:      kbinfo KB319759