In his recent article "Setting up Sendmail to host multiple domains," Thomas Nooning walked through the configuration of this popular mail server to manage multiple virtual domains. If you're running Microsoft Exchange 2000 and looking for the same functionality, don't worry: Exchange 2000 allows for a similar setup of managing multiple domains. This article will show you how to accomplish it.
To help explain the configuration changes needed for Exchange 2000 to host multiple domains, we'll create a scenario to work with. Let's assume that you are the IT administrator of ABC Company, a construction holding company. ABC Company has just purchased XYZ Company, a small but highly profitable and well-known construction company.
Both organizations must maintain separate operations; however, IT functions will be centralized at ABC Company. You have pitched the idea to management to host both companies’ e-mail on your high-end Exchange 2000 Server to reduce servers and administration. Your plan is to host the abcinc.net and xyzinc.net domains on your server, which is named ABC-Server.
Management has given its approval, but it reminded you of the need to maintain separate operations of the two companies. This means that ABC Outlook users should see only ABC employees in their Global Address Book, and XYZ Outlook users should see only XYZ employees in theirs. The companies should also maintain two separate public folders.
Make a new public folder tree
Your first step is to create an additional public folder tree for XYZ Company. To do this, display the administrative groups within System Manager. Select the Folders container, right-click, and choose New | Public Folder Tree (Figure A). Name this new tree XYZ Public Folder Tree.
You might logically assume that this process is needed in order to maintain separate public folder trees for the two companies. In a way, this is the case; however, MAPI clients such as Outlook can view items only in the default public folder tree, rendering the additional tree useless (we will address this shortly). Rather, the new tree is needed to create a new public folder store, as described below.
Set up a storage group
The creation of a new XYZ Company storage group is desired for several reasons. The main reason is so that you can maintain separate e-mail and mailbox administrative policies. To create a storage group for XYZ Company, select the ABC-Server container under Administrative Groups. Right-click and choose New | Storage Group (Figure B).
Name this new storage group XYZ Storage Group. This group will contain at least one public store to hold public folders and one mailbox store to hold mailboxes. Create a new mailbox store named XYZ Mailbox Store by right-clicking on XYZ Storage Group and choosing New | Mailbox Store. Then, create a new public folder store and associate it with the XYZ public store tree.
Set up recipient policies
ABC-Server should already have a default recipient policy to create e-mail addresses for users with an abcinc.net SMTP domain name. Now you will want to create a new recipient policy to handle the creation of the new xyzinc.net SMTP domain name for the XYZ Storage Group mailboxes.
Locate the Recipient Policies applet under the Recipients container. Right-click Recipients Policies and choose New | Recipient Policy (Figure C). Select E-mail Addresses and call the new recipient policy XYZ E-mail Address Policy. Then, modify the filter to display the mailbox storage group XYZ Storage Group. On the E-mail Addresses tab, change the SMTP address to @xyzinc.net. This will ensure that each mailbox created within the XYZ Storage Group has an @xyzinc.net SMTP domain name.
Configure the global address list
As we mentioned earlier, management has requested that when employees access their global address list, they see only their respective company’s information. To accomplish this, create a new global address list for both ABC Company and XYZ Company. Just right-click on All Global Address Lists under the Recipients container and choose New | Global Address List (Figure D). Name the lists ABC Address List and XYZ Address List, respectively.
Set the filter rules for each to show the appropriate storage group. You can now delete your default global address list. Now, when users select the global address list within Outlook, they will see all the users who share the same storage group.
SMTP virtual server and connector
As the IT administrator, you want to handle both abcinc.net and xyzinc.net SMTP mail the same way. There is no additional configuration needed for the SMTP virtual Server or for the SMTP connector, if it's installed. As long as the correct MX records exist for each domain and a recipient with that domain name and e-mail address exists within the Exchange organization, mail will be delivered. If, however, you want to establish two different policies, based on the SMTP domain, to handle the way incoming and outgoing mail is treated, additional configuration may be needed for both the SMTP virtual server and SMTP connector.
You are now ready to create new users and/or mailboxes for XYZ Company. You can use the New User Wizard within Active Directory Users And Computers to create the users and their mailboxes. Ensure that you create the new mailbox in the XYZ Storage Group (Figure E). Once you do this, give the system a minute or two for the Recipient Update Service to run.
Now take a look at the e-mail address for the user. You will see that the user has a firstname.lastname@example.org SMTP e-mail address (Figure F). Also, as before, when new ABC Company users and mailboxes are created, the SMTP address will be displayed as email@example.com. The users are now ready to send and receive SMTP e-mail for their respective domains.
Opening Outlook for the user will reveal that the global address list shows only the recipients for that storage group. But back to the public folder dilemma: Remember that management wants to maintain separate public folder views. However, due to limitations in MAPI clients such as Outlook, the default public folder tree is displayed. Only applications, Web browsers, and IFS shares can access the additional public folder tree.
To work around this issue, create two root public folders and security groups, one called ABC Company and the other called XYZ Company. Now assign the appropriate permissions to the root folders to allow only members of the appropriate group to view the folder along with its contents. This may seems like a crude workaround, but it does accomplish the objective—at least until there is an update to Microsoft’s Outlook client.
As with the scenario we covered in this article, you may someday be faced with the task of configuring Exchange 2000 to host more than one domain. The task requires some advanced administrative knowledge of Exchange, but it's a straightforward task. By following the steps we've looked at here, you'll be able to efficiently configure your Exchange server to handle multiple domains.
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