Exchange Server Cookbook

7.17. Sharing an SMTP Domain Between Exchange and a Foreign Mail System

Problem

You have another mail system within your organization that must share the same SMTP domain namespace with Exchange and you need them to coexist.

Solution

Using a graphical user interface

If you need to use the foreign mail system as the final authoritative system:

1. Open the Exchange System Manager (Exchange System Manager.msc).

2. Expand the organization→ Recipients→ Recipient Policies.

3. Right-click the default policy and select Properties.

4. Click the E-mail Addresses tab.

5. Click New, select SMTP Address, and click OK.

6. Fill in the Address field with the value @ local and click OK.

7. Check the checkbox beside the new SMTP domain and click Set as Primary.

8. Click Apply. When you are asked if you wish to apply the change to all recipients, click Yes. You may be asked this multiple times.

9. Open the property sheet of the recipient policy that contains the domain you wish to share.

10. Click the E-mail Addresses tab.

11. Click Edit and clear the This Exchange organization is responsible for all mail delivery to this address checkbox. Click OK twice.

12. Create a new recipient policy and name it User Addresses.

13. Click the Filter tab, click Modify, and adjust the filter to apply to all users. Click OK on the Find Exchange Recipients screen.

14. Click the E-mail Addresses tab and set the shared domain as the primary address. Click OK.

15. Create a new SMTP connector (see Recipe 7.4) with an address space of the shared domain. This connector should have the ...