Lesson 1: The Microsoft Mail Connector
The Microsoft Mail Connector is responsible for message transfer between Exchange 2000 Server and MS Mail postoffices. Theoretically, every Exchange 2000 server can run an instance of the MS Mail Connector. However, you cannot connect a particular MS Mail postoffice to the same Exchange 2000 Server organization multiple times. One connector can service multiple MS Mail postoffices concurrently. You can configure dedicated connector servers to run the MS Mail and other connectors for the entire organization.
This lesson covers the architecture of the MS Mail Connector in depth by explaining its message handling. The lesson also discusses how to configure the MS Mail Connector.
At the end of this lesson, you will be able to:
- Identify the components of the MS Mail Connector for exchanging messages between Exchange 2000 Server and MS Mail.
- Describe the path a message takes through the MS Mail Connector.
- Configure and use the MS Mail Connector.
Estimated time to complete this lesson: 75 minutes
MS Mail Connector Overview
The MS Mail Connector is an additional component that comes with both the Standard and Enterprise Edition of Exchange 2000 Server. One MS Mail Connector is sufficient to connect an entire Exchange 2000 Server organization to an MS Mail network. The MS Mail Connector enables you to connect separate MS Mail networks together or provide MS Mail users with connectivity to foreign messaging systems, such as systems that support the Simple Mail Transfer Protocol (SMTP) or X.400 (see Figure 26.1). Exchange 2000 Server can replace existing MS Mail gateways and legacy MS Mail Message Transfer Agents (MTAs), and it can replace an entire MS Mail infrastructure altogether. Based on the MS Mail Connector, a seamless migration to Exchange 2000 Server is possible.
Figure 26.1 Deploying the Microsoft Mail Connector
MS Mail Connector Installation
You can install the MS Mail Connector using the Exchange 2000 Server Setup program. On the Component Selection wizard screen, select Install for the Microsoft Exchange MSMail Connector component. If you want to add the connector to an existing Exchange 2000 Server organization, you must have the permissions of an Exchange Administrator in the administrative group where the target routing group exists. You can read more about the installation of Exchange 2000 Server in Chapter 5, "Installing Microsoft Exchange 2000 Server."
Important Connector Components
The MS Mail Connector comes with a number of components, such as an MS Mail Connector Interchange service, a connector postoffice (Connector PO), a proxy address generator DLL, and address details templates. During the connector installation, connector configuration objects are created in Active Directory. Further elements are added to the installation when you configure the MS Mail Connector in Exchange System Manager (that is, MS Mail Connector MTA services). Exchange System Manager provides the administrative user interface to manage MS Mail Connector instances.
After the installation of an MS Mail Connector in a routing group, the following separate configuration objects are available in Exchange System Manager:
- Connector for MS Mail. Located under <Organization Name>/Administrative Groups/<Administrative Group Name>/Routing Groups/<Routing Group Name>/Connectors, this configuration object allows you to manage the connector parameters that relate to message routing and transfer.
- Connector for MS SchedulePlus FreeBusy. Located under <Organization Name>/Administrative Groups/<Administrative Group Name>/Routing Groups/<Routing Group Name>/Connectors, this configuration object allows you to specify configuration settings for the Schedule+ Free/Busy Connector.
- Connectors. The Connectors container object itself provides access to the Dirsync Server and Dirsync Requestor commands, which enable you to configure the Microsoft Directory Synchronization Agent (DXA) as an MS Mail Dirsync server or Dirsync requestor.
- Directory synchronization. Located under <Organization Name>/Administrative Groups/<Administrative Group Name>/Servers/<Server Name>, this configuration object allows you to map address details for directory synchronization between MS Mail and Exchange 2000 Server.
MS Mail Dirsync and Schedule+ Free/Busy Connector are explained in subsequent lessons in this chapter.
MS Mail Message Routing in Exchange 2000 Server
As outlined in Chapter 3, "Microsoft Exchange 2000 Server Architecture," the SMTP transport engine works in conjunction with the MTA to handle message transfer to foreign messaging systems, including MS Mail.
Address Spaces
Routing decisions are made based on address spaces that you can add to an MS Mail Connector instance implicitly or explicitly. For every connection to an MS Mail postoffice, configured via the Connections tab of the Connector for MS Mail configuration object, an implicit address space is created. Via the Address Space tab, you may modify existing address spaces or add new entries explicitly. Furthermore, the Address Space tab allows you to restrict the availability of a connector instance to the local routing group. In this case, activate the Routing Group option under Connector Scope. By default, MS Mail Connector instances are available to the entire organization. The purpose and configuration of address spaces is covered in Chapter 16, "Message Routing Administration."
Outbound and Inbound Message Transfer
Address spaces are stored in the routingList attribute on the connector object in Active Directory. On every server startup, this information is incorporated into the link state table (LST) to allow Exchange 2000 Server to route messages to the connector. The MTA receives outbound MS Mail messages from the SMTP routing engine via its message queues in the Information Store and places them in an internal message queue for the MS Mail Connector queue, which is an internal MTA queue not maintained by the Information Store. You can view this queue in Exchange System Manager under <Organization Name>/Administrative Groups/<Administrative Group Name>/Servers/<Server Name>/Protocols/X.400/Queues, such as Blue Sky Airlines (Exchange)/Administrative Groups/First Administrative Group/Servers/BLUESKY-SRV1/Protocols/X.400/Queues. Message queues are covered in Chapter 20, "Microsoft Exchange 2000 Server Maintenance and Troubleshooting."
Message Conversion
The MS Mail Connector receives messages from the MTA, converts them into MS Mail format, and sends them to their destination postoffices. For outbound messages, the connector also needs to replace Exchange address information with MS Mail addresses for sender and recipients. When inbound messages must be delivered to an Exchange recipient, the MS Mail Connector gathers them from MS Mail postoffices, converts them, and transfers them to the MTA. The MTA passes them to the SMTP routing engine for further delivery. The interaction of the MTA with the SMTP service was explained in Chapter 3, "Microsoft Exchange 2000 Server Architecture."
MS Mail Connector Architecture
An Exchange 2000 server running the MS Mail Connector is seen as a native MS Mail postoffice to the MS Mail network. Using the MS Mail Administrator program, you must register those Exchange 2000 servers as External Postoffices on each existing MS Mail postoffice. MS Mail users can then send messages to recipients in the Exchange 2000 Server organization.
The MS Mail Connector Interchange
The MS Mail Connector Interchange service works between the MTA and the Connector Postoffice (PO) (see Figure 26.2). It converts messages from Exchange format to MS Mail format and vice versa. The MS Mail Connector Interchange polls the Connector PO to find inbound messages. However, this service is configured to start manually, by default. It is a good idea to set this service to automatic startup via the Services utility in the Administrative Tools program group.
NOTE
Messages displayed in the Connector for MS Mail (<Server Name>) queue of the MTA have not yet been received by the MS Mail Connector Interchange. A filled queue might indicate MS Mail Connector Interchange problems.
Figure 26.2 Components of the Microsoft Mail Connector
The Connector PO
It is the Connector PO that forms the actual MS Mail interface of Exchange 2000 Server. This postoffice is in the \Program Files\Exchsrvr\Connect\Msmcon\Maildata directory, which is also shared as Maildat$ for network access. Every Connector PO has a serial number of 22-28798. In fact, the Connector PO is a real MS Mail postoffice that stores messages in MS Mail format. However, it functions solely as an intermediate repository and has no user mailboxes.
Using Exchange System Manager, you can examine the queues in the Connector PO. Display the Connections tab of the MS Mail Connector that you are interested in. Select the desired postoffice under Connections, and then click Queue. If messages remain in the Connector PO, a corresponding MS Mail Connector MTA service may require configuration adjustments.
NOTE
Native MS Mail postoffices see an Exchange 2000 server as an MS Mail postoffice, which you must configure as an external postoffice within MS Mail. All Exchange users, regardless of their home servers, are handled as MS Mail users residing on the Connector PO.
MS Mail Connector MTAs
MS Mail Connector MTAs transfer messages between the Connector PO and the MS Mail network, just as any MS Mail MTA does. MS Mail MTAs are also referred to as MS Mail Externals. An MS Mail Connector MTA is the Exchange 2000 Server equivalent of a regular MS Mail External or the Multitasking MTA provided with MS Mail 3.5. MS Mail Connector MTAs are implemented as Windows 2000 services, which are created during the MS Mail Connector configuration. A particular MS Mail Connector MTA service is not necessarily responsible for all MS Mail postoffices that can be reached through the MS Mail Connector. You can control the list of serviced postoffices using the Connector MTAs property sheet. Up to 10 MS Mail Connector MTA services can run on one Exchange 2000 server.
An MS Mail Connector MTA polls all postoffices for which it is responsible, including the Connector PO. If it detects messages in any outgoing queue, it transfers them to their destinations through the MS Mail network. The message queues in each postoffice determine the MS Mail routing of messages.
NOTE
The MS Mail Connector MTA transfers messages only between the Connector PO and any MS Mail postoffices. Therefore, regular MS Mail MTAs must be used if the Exchange 2000 server is not included in the message path between two MS Mail postoffices (see Figure 26.2).
Supported Communication Mechanisms
The MS Mail Connector MTA supports local area network (LAN) and asynchronous connections. It can transfer messages directly from postoffice to postoffice if a LAN exists using the NetBEUI, Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX), or TCP/IP protocol. With asynchronous connections, a remote MTA must be contacted. The remote communication partner (another MS Mail MTA) answers the incoming call, receives the messages, and places them in the appropriate destination postoffice. To ensure full compatibility with MS Mail MTAs, the MS Mail Connector MTA uses the old-style MS Mail modem scripts to control a modem. The appropriate modem script must be copied in the \Maildata\GLB directory of the Connector PO. Only the four standard ports (COM1-COM4) are supported.
NOTE
The MS Mail Connector MTA is limited to postoffice-to-postoffice communication. Remote MS Mail clients cannot dial into an MS Mail Connector MTA to send or receive messages.
Native MS Mail MTAs and MS Mail Gateways
MS Mail MTAs perform the message interchange between postoffices in a native MS Mail network. They can be used even if an Exchange 2000 server has been integrated because they treat that server as a native MS Mail postoffice. However, the MS Mail Connector is more powerful and should replace MS Mail MTAs, if possible.
The integration of Exchange 2000 Server and MS Mail can be advantageous for both sides. As mentioned earlier, MS Mail users can use existing Exchange connectors. Exchange users, on the other hand, can also benefit from older gateways installed in the MS Mail network, such as an MS Mail Gateway to System Network Architecture Distributed Systems (SNADS). You can even install MS Mail gateways directly on the Connector PO. However, if possible, you should replace all existing MS Mail gateways with corresponding Exchange 2000 Server connector instances. You need to update the gateway access component on the MS Mail postoffices to indicate the Connector PO on the Exchange 2000 server as the gateway postoffice.
Configuring the MS Mail Connector
Exchange System Manager and the Services utility are the primary tools to manage MS Mail Connector instances. First you must configure the connector through its corresponding Connector for MS Mail (<Server Name>) object in Exchange System Manager. You must specify the postoffices you want to connect to, and you must configure MS Mail Connector MTA services. After that, you need to start the MS Mail Connector Interchange service and MS Mail Connector MTA services using the Windows 2000 Services utility. It is a good idea to configure all MS Mail Connector services to start automatically.
NOTE
If you change the MS Mail Connector configuration, you must stop and restart the MS Mail Connector Interchange service or the MS Mail Connector MTA services—depending on which service is affected by your changes—before the changes will take effect.
MS Mail Connector Interchange Settings
When you right-click on the Connector for MS Mail (<Server Name>) object, such as Connector for MS Mail (BLUESKY-SRV1), and then select Properties, you can configure the MS Mail Connector. The Interchange tab is displayed. Here you need to specify an Administrator's Mailbox. In fact, you cannot click on any other tab until you specify a mailbox. This mailbox receives special connector messages, such as notifications about undeliverable items.
Using the Interchange tab, you also can set the code page for the connector under Primary Language For Clients and determine whether to maximize MS Mail 3.x compatibility. If all of your Exchange and MS Mail users are using Outlook as their e-mail client, you may deselect the Maximize MS Mail 3.x Compatibility check box to reduce the size of messages with embedded objects sent from Exchange users to MS Mail recipients. Furthermore, you can enable message tracking, which was covered in Chapter 20, "Microsoft Exchange 2000 Server Maintenance and Troubleshooting."
Connector PO Details and User Addresses
The name of an MS Mail postoffice, such as the Connector PO, consists of a network name and a postoffice name, as in MSMAILNET/MSMAILPO. Both names are used for message routing. A complete MS Mail address also includes the name of a mailbox, as in MSMAILNET/MSMAILPO/MSMAILMBX. For example, the Exchange user named Administrator could possess the proxy MS Mail address BLUESKYAIR/FIRSTADMIN/ADMINISTRA. Network, postoffice, and mailbox names cannot be longer than 10 characters each. You can examine your MS Mail proxy addresses on the E-Mail Addresses property sheet in Active Directory Users and Computers. The address type is MS.
Do not get confused because MS Mail proxy addresses are not assigned auto-matically to mailbox-enabled Exchange user accounts. As mentioned in Chapter 13, "Creating and Managing Recipients," the Recipient Update Service is responsible for proxy address assignments, yet MS Mail proxy addresses are not enabled by default. To generate and assign them, open the corresponding recipient policy, such as the default policy object under <Organization Name>/ Recipients/Recipient Policies, in Exchange System Administrator. Click on the E-Mail Addresses tab, and select the MS check box to activate the proxy address generation.
It is important to note that the proxy address format is determined using the name of the Connector PO, as displayed in the Local Postoffice tab of the MS Mail Connector object. Here, you can change the postoffice or network name. However, you need to keep in mind that these modifications affect the proxy MS Mail addresses of all users. Messages addressed to the old Connector PO name will not be delivered and result in nondelivery reports. Consequently, you must update the recipient policy to assign your users correct MS Mail proxy addresses.
NOTE
All Connector POs in the organization must have the same NETWORK/POSTOFFICE name.
To give an example, let's say you want to change the Connector PO name on BLUESKY-SRV1 from BLUESKYAIR/FIRSTADMIN to BLUESKYAIR/ EXCHANGE. Display the MS Mail Connector properties in Exchange System Manager, switch to the Local Postoffice tab, and change the name under Postoffice to EXCHANGE. When you click OK, a Change Local Network/Postoffice Name dialog box appears, informing you about the tasks that have to be accomplished next. Read the information carefully, and then click Continue to close this dialog box. After that, open the Default Policy from the Recipient Policies container, click on the E-Mail Addresses tab, double-click the MS Mail proxy address entry, and, in the Microsoft Mail Address Properties dialog box, under Address, change the information to BLUESKYAIR/EXCHANGE. Click OK twice, and, in the Exchange System Manager dialog box informing you that corresponding e-mail addresses will be updated to match these new addresses, click Yes. The update of address information will take place according to the configuration of the Recipient Update Service.
NOTE
If you change the name of the Connector PO, you must restart the MS Mail Connector Interchange and all MS Mail Connector MTA services using the Services utility to update their network/postoffice name list. You also need to update the external postoffice information in all MS Mail postoffices using the MS Mail Administrator program.
Specifying MS Mail Postoffices in a LAN
An MS Mail Connector transfers messages only to postoffices specified in the Connections tab. To specify a new postoffice, click Create. This displays the Create Connection dialog box, where you need to click Change and specify the Universal Naming Convention (UNC) path to the postoffice in the Postoffice Path box. The network name and postoffice name are obtained automatically from the specified postoffice.
If additional postoffices can be reached indirectly through the specified MS Mail postoffice, you can have them referenced implicitly by clicking the Upload Routing button. Information about indirectly accessed postoffices is then gathered from MS Mail, thus creating references automatically. You need only select the desired entries and click OK. An associated address space is created for the direct postoffice and all selected indirect postoffices (see Figure 26.3).
Figure 26.3 Indirect message routing to Microsoft Mail postoffices
NOTE
You cannot use the Upload Routing feature for connections made through asynchronous connections. The required configuration parameters change if you select the Async option instead of LAN in the Create Connection dialog box. However, you can use the Indirect option to specify a postoffice indirectly through another postoffice.
Creating Connector MTAs
An MS Mail Connector without an MS Mail Connector MTA service is like a car without wheels. It is useless to deliver messages to the Connector PO using the MS Mail Connector Interchange service if there is no service that obtains them and delivers them. As mentioned earlier, MS Mail Connector MTA services must be created explicitly. To create a new Connector MTA instance, in the Connector MTAs tab of the MS Mail Connector object, click New. In the New MS Mail Connector (PC) MTA Service dialog box, specify a descriptive Service Name and other options such as the Polling Frequency. The Service Name is particularly important because it identifies the corresponding Windows 2000 service in the Services utility. Every MS Mail Connector MTA service can be configured to start either automatically or manually. To examine the startup setting, click the Options button. Click OK to create the new Connector MTA instance, which will be displayed in the Connector MTAs tab under MS Mail Connector (PC) MTA Services.
Once you have created an MS Mail Connector MTA service, you must specify the Postoffices Serviced by clicking the List button. Select the desired postoffice, click Add, and then click OK. You must repeat these steps for all direct postoffices. You must start the MS Mail Connector MTA service manually after you complete the configuration.
Configuring the MS Mail Environment
Using the MS Mail Administrator program, you must also configure each MS Mail postoffice; otherwise, MS Mail users will not be able to send messages to Exchange users. As mentioned, you must configure the Connector PO as a regular external postoffice.
To define the Connector PO in an MS Mail Postoffice
- Start the MS Mail Administrator program, and log on using your administrator account. Type E for External-Admin, and then C for Create.
- In the Enter Network Name box, type the network name of the Connector PO (such as BLUESKYAIR), and then press ENTER.
- In the Enter Postoffice Name box, type the postoffice name of the Connector PO (such as EXCHANGE), and then press ENTER.
- Select Direct under Select Route Type, and then press ENTER.
- For connections in a LAN, select MS-DOS Drive under Direct Connection Via, and then press ENTER.
- Press Enter again to confirm the configuration, and create the External postoffice. Press ESC twice, and then press ENTER to exit the MS Mail Administrator program.
It is a very good idea to check the message transfer from Exchange to MS Mail and vice versa. Successful message transfer in one direction does not imply that messages can also travel in the opposite direction. Keep in mind that it might take several minutes for test messages to arrive in your Inbox. If you want to track the movement of messages in MS Mail, open the MS Mail Administrator program, and check the queue for the external Connector PO. If messages remain in this queue for an extended period, use the Services utility to verify that the MS Mail Connector MTA service has started. In Exchange 2000 Server, messages may remain in the MTA queue for the MS Mail Connector or in the Connector PO if the MS Mail Connector Interchange service is not running.
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