Many situations require you to manage multiple domains in Exchange. For example, following a company merger, you might need to host more than one domain. Whatever the case may be, there’s an obvious need for this functionality, and Exchange 2000 offers features to fill that need.

In a previous TechRepublic article, Del Smith offered instructions for setting up multiple domains in Exchange 2000, but some users have encountered problems with the process. Responses to questions in our Technical Q&A forums on the subject show that hosting multiple domains does have some trouble spots. Here’s a look at one member’s situation and some of the tips that other members offered in response.

Setup options
Donald Morrison, training manager for Coastal Computers, said he read Smith’s article and had followed previous threads in the Tech Q&A forums on the topic but was unable to get multiple domain hosting working on his network.

“I have one [Windows] 2000 server hosting three Web sites and need Exchange to host these three SMTP servers,” he wrote.

Morrison said that he was unable to complete the new mailbox store setup and was looking for general advice on setting up multiple-domain hosting and completing the mailbox configuration.

TechRepublic members responded with detailed explanations about how to accomplish the task.

Member Steve Merrill explained that an important initial step is setting up additional SMTP virtual servers. He offered the following instructions:

  1. Run Exchange System Manager.
  2. Navigate to SMTP.
  3. Right-click on SMTP and choose New | SMTP Virtual Server.
  4. Follow the steps in the New SMTP Virtual Server Wizard.

Following the procedures outlined in the wizard sets up the necessary SMTP servers.

Merrill noted that the IP address/TCP port combination for each SMTP virtual server must be unique. In other words, two SMTP virtual servers can use the same TCP port as long as the IP addresses are different.

“If the SMTP virtual server will be using a new IP address,” Merrill added, “you will have to first configure that new IP address before it can be used by Exchange.”

Member JordanA of ITSHOP, however, said that you don’t necessarily have to set up additional virtual servers. He offered the instructions  below as an alternative for making the setup work.

First, set up MX records to point to a single server by creating host records in the DNS zones for each domain.

“For instance,” JordanA said, “I have two domains: and In my DNS zones, I have created two host records,, and,”

After you create host records, you also need to create MX records for each domain. The following examples show how this would be done for JordanA’s domains: = =

Use the default server priority of 10.

After setting up the host records in the DNS zones, you must configure Exchange, following these steps:

  1. Open Exchange System Manager.
  2. Expand the Global Settings tree.
  3. Double-click on Internet Message Formats. You’ll see the domains for which you accept mail displayed in the right pane.
  4. Right-click on Internet Message Format and choose New | Domain.
  5. Type the domain name in the format, if it isn’t already there.
  6. Type the names for all domains following the same steps.

“Exchange will now receive mail for valid e-mail addresses for the two domains,” JordanA said. “[But] you still need to create the addresses for the users.” To do that, he offered the following instructions:

  1. Expand the Recipients tree.
  2. Double-click Recipient Policies.
  3. Double-click the default policy and select the E-mail Addresses (Policy) tab.
  4. Click New and choose SMTP Address.
  5. In the Address box, type and click OK.
  6. Perform the same steps for each additional domain.
  7. Right-click on the default policy and choose Apply This Policy Now.
  8. Open Active Directory Users And Computers and select a user. In this scenario, the user should have e-mail addresses for both and

JordanA recommended testing the domain addresses by sending test messages to ensure that the addresses function properly.

If you’re having trouble configuring multiple domains in Exchange 2000, these member tips may help you approach the problem from a different angle. Another good source of information on Exchange issues is the Web site, which offers articles covering a wide array of Exchange features and challenges, including detailed configuration instructions. And if you still can’t find the answers you’re looking for, you can always search the Knowledge Base at Microsoft’s support site or Microsoft TechNet.