How to Specify an Address Space for the Connector


A connector's address space defines the domain or range of domains to which a connector sends mail. You can specify which address groups that a specific connector will handle. If you use multiple SMTP connectors to route Internet mail, at least one connector should have an address space of * (asterisk). The asterisk represents all external domains.

Before You Begin

Before you perform the procedure in this topic, read Connecting Exchange to the Internet.

The following permissions are required to perform this procedure:

  • Member of the local administrators group and a member of a group that has had the Exchange Administrators role applied at the administrative group level


To specify an address space for the connector

  1. In the SMTP connector Properties, click the Address Space tab.

  2. Click Add. The Add Address Space dialog box appears.

    The Add Address Space dialog box


  3. Under Select an address type, click SMTP, and then click OK. The Internet Address Space Properties dialog box appears.

    The Internet Address Space Properties dialog box



    In Internet Address Space Properties, in the E-mail domain box, there is a default value of . The represents all addresses. At least one connector in your organization should have this address space to ensure that all external domains are routed to the Internet.

  4. In Internet Address Space Properties, in the E-mail domain box, type an e-mail domain for the connector. In the Cost box, assign an appropriate cost for this connector. For example, if you want all users to always use this connector and only use a backup connector if this connector is unavailable, assign this connector a cost of 1 and assign the secondary connector a higher cost. Remember that Exchange always chooses the route with the lowest cost, if that route is available.


    Do not list your inbound domains on an SMTP address space for a connector. Your inbound domains are listed in your recipient policies. If some or all of your inbound domains are listed, you may receive NDRs that indicate a mail loop (these NDRs may have the diagnostic code 5.3.5). By specifying domains on the Address Space tab, you can configure these domains as routable domains.

  5. Click OK to return to the Address Space tab.

  6. Under Connector scope, select one of the following based on your routing topology:

    • Select Entire organization if you want users in any routing group to be able to send Internet mail through this connector. With this option selected, all Exchange servers in the organization can route mail through this connector to the Internet.

    • Select Routing Group if you want only users in this bridgehead server's routing group to send mail through this connector.


      For more information about assigning costs and scoping, see Understanding Connector Scope and Restrictions.

  7. If you want mail to be relayed through your system to the domains that you specified, select the Allow messages to be relayed to these domains check box.


    Do not select this check box if you are creating a connector with an address space of *.

  8. Click OK.