Use an Exchange Server as an MS Mail post office

Many companies that merge want to connect Exchange Server 5.5 systems that have different organization names. Exchange servers that use the directory replication connector (DRC) to share their directory data must have the same organization name.

The Move Server Wizard (MSW) is a sophisticated tool for changing an Exchange server's organization name. This method lets you connect with full functionality (e.g., public folders replication). Tony Redmond, "Move Server Wizard War Stories," August 1999, offers some tips about using the wizard. Although the wizard is one of the most effective and permanent methods for connecting directories, it is complicated and time intensive to use because you must accomplish tasks such as rehoming public folders on the migrated machine after the wizard runs.

Another method, Compaq's Lightweight Directory Access Protocol (LDAP) Directory Synchronizer Utility (LDSU), uses LDAP updates to synchronize directories. However, this method and others like it usually involve costs that you can avoid if you have the expertise to use the method I describe here.

When you need only to establish mail flow and exchange address lists, you can use another method based on Exchange Server's built-in functionality to act like a Microsoft Mail (MS Mail) post office. You can use an MS Mail connector to connect another Exchange server that will act like an MS Mail post office. You can then use the External and Dispatch services for directory synchronization. To use this method, you need to modify Exchange Server.

In this article, directory synchronization means exchanging address lists between MS Mail and Exchange or MS Mail to MS Mail, and directory replication means Exchange-to-Exchange directory replication using the directory replication connector.

MS Mail
Before Microsoft introduced Exchange Server, MS Mail Server was the most commonly used messaging platform. An MS Mail server is simply a shared-file system that hosts all address lists and user mailboxes. This file structure usually consists of a maildata directory and many subdirectories. In addition, a DOS program and, later, a Windows NT service called External connected other MS Mail servers; External was the early version of the Exchange Message Transfer Agent (MTA).

The Dispatch program extracts address list updates from every MS Mail Server post office, and the External program uses messages to transport the updated files to the directory synchronization (Dir-Sync) server. The Dir-Sync server collects all address list updates and sends back the new address lists to the Dir-Sync requestor post offices. The Dispatch service again collects the updates from the Dir-Sync requestor post offices and imports them into the MS Mail address lists.

Exchange's Hidden MS Mail Post Office
If you install Exchange Server with an MS Mail connector (e.g., on the C drive), a bin directory in C:\exchsrvr\connect\msmcon contains the MS Mail admin.exe program and a maildata directory that has a directory structure similar to an MS Mail Server directory structure. You can use the hidden share \\servername\maildat$ to access an Exchange server through this hidden MS Mail post office from every other MS Mail server on the LAN.

Every MS Mail post office has a unique sign-on ID, which an external MS Mail post office needs to connect through an asynchronous connection. An MS Mail connector on Exchange also has this sign-on ID. As Figure 1 shows, you can see the Sign-on ID in the Microsoft Exchange Administrator program by going to Connections, MS Mail Connector, then clicking the MS Mail Connector Properties Local Postoffice tab.

Exchange Server assigns this ID number (e.g., 22-28798) during installation, and Exchange Server documentation states that you can't change it. However, this statement isn't true. You can use the MS Mail Postoffice Serialization Utility to modify this ID number in the master.glb file on the MS Mail Server post office installation disk. The TechNet article "How to Use the Microsoft Mail for PC Networks Serializer" explains how to obtain and install the utility.

To create a new master.glb file with a new ID number, start the serial.exe program and select Serialize Setup Diskette from the main menu. Use the disk to install an MS Mail server. In this case, installing a MS Mail server means only that Setup copies the files from the installation disk to the hard disk. During the installation, use the same network and post office names as the MS Mail connector, as Figure 1 shows.

Finally, copy the modified master.glb file from the MS Mail post office maildata\glb directory to the hidden post office on the Exchange server in C:\exchsrvr\connect\msmcon\maildata\glb. Check the Local Postoffice tab in the MS Mail Connector Properties to verify that copying the file has changed the Sign-on ID number. Now, you can use a remote MS Mail connector to connect this Exchange server to another Exchange server over the LAN or an asynchronous connection.

Configuring an Exchange Server as a Dir-Sync Server
MS Mail post offices that participate in directory synchronization are called requestors and work with a Dir-Sync server. Microsoft designed Exchange Server to be able to act as a Dir-Sync server against MS Mail requestors.

To set up an Exchange server as a Dir-Sync server, from Exchange Administrator, go to File, New Other, Dir-sync server. On the General tab of the Dir-Sync server's Properties dialog box, specify a Dir-Sync server name and an administrator's mailbox that you can use for debugging the Dir-Sync messages. On the Schedule tab, enter the time you want your Exchange server to send address list updates to the requestors. Exchange processes incoming updates automatically when the server receives them.

You must set up a remote Dir-Sync requestor for every remote Exchange server that is acting as a Dir-Sync requestor. However, before you can set up the remote Dir-Sync requestor, you must set up the connection to the remote post office in your MS Mail Connector. On the MS Mail Connector Properties Connections tab, select Create to set up the route to the remote post office. In this example, the network name is CYBERDYNE and the remote post office name is REMOTE, as Figure 2 shows. Go to the Connector MTAs tab, and click New to create an MTA instance to service the remote post office, as Figure 3 shows.

Now, set up a remote Dir-Sync requestor for this remote post office. In Exchange Administrator, select File, New Other, Remote Dir-sync Requestor. In the dialog box that Figure 4 shows, select CYBERDYNE/REMOTE and click OK. On the MS Mail Connector Properties General tab, enter a name for the remote Dir-Sync requestor. Notice that the Dir-Sync Address field contains a system address that Exchange uses for synchronizing. On the Import Containers tab of the remote requestor's properties dialog box, enter the recipient container for storing the address list information that comes from this remote requestor. On the Export Containers tab, specify the recipient containers (addresses) you want to export. In Export, you must include among the containers that you want to export the recipients that you selected as the import container; otherwise, the address list of Requestor 1 will be missing on Requestor 2.

Configuring the Exchange Server as the Dir-Sync Requestor
Now, you must configure the other end—you must configure the remote Exchange server as a Dir-Sync requestor. Microsoft intended to use an Exchange server that is the remote requestor against an MS Mail post office, but the process also works against an Exchange server that is a Dir-Sync server. In Exchange Administrator, choose the name of your Dir-Sync server at the prompt. You must define the Dir-Sync server in the MS Mail connector in advance; therefore, you must have enabled mail connectivity. On the General tab of the requestor's Properties dialog box, enter a name for the requestor. On the Import Containers tab, specify the recipient container that will receive updates from the server. The Export Containers tab specifies all containers that you will export. Also, on the Settings tab, select the Send updates, Receive updates, Import on next cycle and Export on next cycle check boxes.

During the requestor setup, Exchange Server creates a hidden custom recipient in the standard recipients container. Exchange needs this custom recipient to update routing information. If you later want to replace this MS Mail directory synchronization with full Exchange directory replication, be sure to delete this custom recipient first. Otherwise, Exchange will replicate it to the server that is the Dir-Sync server and prevent the server from accepting updates because the system would be hosting duplicate email addresses (e.g., MS:CYBERDYNE/REMOTE/$SYSTEM). For directory synchronization tips, see the Web-exclusive sidebar "Troubleshooting Directory Synchronization" on the Exchange Administrator Web site (http://www.exchangeadmin.com/).

Using an Exchange Server as an MS Mail Post Office
Using and connecting a remote Exchange server as an MS Mail post office can be an easy way to establish simple mail connectivity and address list synchronization when you're connecting two Exchange servers that don't have the same organization name. Be aware that Microsoft probably doesn't support this method. However, if you don't want to use the MSW, consider this easy and quick solution.