Configure Exchange 2010 to Route Messages for a Shared Address Space

Applies to: Exchange Server 2010

An organization may have to share the same SMTP address space between two or more different e-mail systems. For example, you may have to share the SMTP address space between Exchange and a third-party e-mail system, or between Exchange environments that are configured in different Active Directory forests. In these scenarios, users in each e-mail system have the same domain suffix as part of their e-mail addresses.

You can use the EMC or the Shell to configure a Microsoft Exchange Server 2010 Hub Transport server to route messages for a shared address space.

Looking for other management tasks related to managing message routing? Check out Managing Message Routing.

Step 1: Create an internal relay domain

You need to be assigned permissions before you can perform this procedure. To see what permissions you need, see the "Accepted domains" entry in the Transport Permissions topic.

To support routing messages for a shared address space, you must create an accepted domain that's configured as an internal relay domain. When you configure an accepted domain as an internal relay domain, Exchange first tries to deliver to a recipient in the Exchange organization. If the recipient isn't found, the message is routed to the Send connector that has the closest address space match.

Use the EMC to create an internal relay domain

1. In the console tree, expand Organization Configuration, select Hub Transport, and then in the work pane, click the Accepted Domains tab.
2. In the action pane, click New Accepted Domain. The New Accepted Domain wizard appears.
3. On the New Accepted Domain page, complete the following fields:
   • Name   Use this field to identify the accepted domain in the user interface. You can type any name that you want. We recommend that you select a meaningful name that helps you easily identify the purpose of this accepted domain. For example, you may want to use a name that identifies this as a subsidiary domain or as a hosted domain. You must use a unique name for each accepted domain.
   • Accepted Domain   Use this field to identify the SMTP namespace for which the Exchange organization will accept e-mail messages. You can use a wildcard character to accept messages for a domain and all its subdomains. For example, you can type *.contoso.com to set Contoso.com and all its subdomains as accepted domains.
4. After you complete these fields on the New Accepted Domain page, select the following option: Internal Relay Domain.
5. Click New.
6. On the Completion page, click Finish.

Use the Shell to create an internal relay domain

This example creates the internal relay domain Contoso for the SMTP domain contoso.com.

New-AcceptedDomain -Name "Contoso" -DomainName contoso.com -DomainType InternalRelay

For detailed syntax and parameter information, see New-AcceptedDomain.

Step 2: Create a Send connector to route e-mail to the shared domain

You need to be assigned permissions before you can perform this procedure. To see what permissions you need, see the "Send connectors" entry in the Transport Permissions topic.

You must also add a Send connector that's sourced on a Hub Transport server and configured to send e-mail to the shared address space.

Use the EMC to create a Send connector to route e-mail to the shared domain

1. In the console tree, expand Organization Configuration, select Hub Transport, and then in the work pane, click the Send Connectors tab.
2. In the action pane, click New Send Connector. The New Send Connector wizard starts.
3. On the Introduction page, follow these steps:
   • In the Name field, type a meaningful name for this connector. This name is used to identify the connector.
   • In the Select the intended use for this connector field, select one of the following usage types for the connector. The usage type determines the default permission sets that are assigned on the connector and grants those permissions to trusted security principals:
     • **Internal   **Select this usage type if the e-mail system with which Exchange 2010 shares an address space is another Exchange 2010 organization.
     • **Internet   **Select this usage type if the e-mail system with which Exchange 2010 shares an address space is a third-party e-mail system.
4. Click Next.
5. On the Address space page, click Add. In the SMTP Address Space dialog box, enter the domain name to which this connector will send mail, for example, contoso.com or *.contoso.com. You may select the Include all subdomains check box to use this connector to send e-mail to all subdomains of the address space. If necessary, you can also provide a specific cost for this connector. When you're finished, click OK. Leave the Scoped send connector check box cleared, and then click Next.
6. On the Network settings page, select Route mail through the following smart hosts. Click Add.
7. In the Add Smart Host dialog box, select IP Address or Fully qualified domain name (FQDN) to specify how to locate the smart host. If you select IP Address, enter the IP address of the smart host. If you select Fully qualified domain name (FQDN), enter the FQDN of the smart host. The sending server must be able to resolve the FQDN. When you're finished, click OK. To add more smart hosts, click Add, and repeat this step. If you want to use a specific list of external DNS servers instead of the DNS servers specified in the adapter settings, select the Use the External DNS Lookup settings on the transport server check box. When you're finished, click Next.
8. On the Configure smart host authentication settings page, select the method that's used to authenticate to the smart host. The following smart host authentication methods are available:
   • None
   • Basic Authentication
   • Basic Authentication over TLS
   • Exchange Server Authentication
   • Externally Secured (for example, with IPsec)
9. Click Next.
10. On the Source Server page, click Add to add a source server. By default, the Hub Transport server that you're currently working on is listed as a source server. In the Select Hub Transport or Subscribed Edge Transport dialog box, select the Hub Transport servers that will be used as the source server for sending messages to the shared address space. When you finish adding source servers, click OK. Click Next.
11. On the New Connector page, review the configuration summary for the connector. If you want to modify the settings, click Back. To create the Send connector by using the settings in the configuration summary, click New.
12. On the Completion page, click Finish.

Use the Shell to create a Send connector to route e-mail to the shared domain

This example creates a Send connector with the following settings:

• Configures the connector as an Internet usage type
• Assigns the address space contoso.com
• Routes messages to the smart host smarthost.contoso.com
• Uses the Externally Secured authentication mechanism
• Sets the maximum message size to 20 megabytes (MB)

New-SendConnector -Name "Contoso.com Send Connector" -Internet -AddressSpace contoso.com -DNSRoutingEnabled $false -SmartHosts smarthost.contoso.com -SmartHostAuthMechanism ExternalAuthoritative -MaxMessageSize 20MB

For detailed syntax and parameter information, see New-SendConnector.