To host email for multiple domains (e.g., mycompany.com, customer1.net, sunday.org) in Exchange Server 5.5, all I need to do is install the Internet Mail Service (IMS) and configure it to accept messages at those domains as Inbound. Now that I have Exchange 2000 Server, I need to host email for multiple domains apart from the mycompany domain. How do I configure my Exchange 2000 box to host multiple domains? Do I need to use SMTP connectors?

Exchange 2000 accepts mail for recipients who have address spaces defined by recipient policies in an Exchange organization. By default, when you install Exchange, the program provides one recipient policy for whatever domain you specify (e.g., mycompany.com). To receive mail for other domains, you can either add new recipient policies for those domains or simply add the additional domains as proxy addresses to your default policy. The latter method is easier for your situation. Here's how to do it:

  1. Open Exchange System Manager (ESM).
  2. Expand the Recipients node, then click Recipient Policies. The list in the right pane shows which recipient policies you've already defined.
  3. Double-click Default Policy to open the Default Policy Properties dialog box.
  4. Switch to the E-Mail Addresses (Policy) tab and click New. When prompted, choose SMTP as the address type.
  5. In the SMTP Address Properties dialog box's Address field, type the domain you want to use, prefixed by the at (@) symbol (e.g., @sunday.org), then click OK.
  6. Note that although the new address appears in the Generation Rules list of the E-Mail Addresses (Policy) tab, it's not selected. Select the new address, then click OK.
  7. Wait for the Recipient Update Service (RUS) to run. If you're impatient, open the Recipient Update Services container in ESM, right-click your domain's RUS, and select Update Now—but you'll still have to wait for it to finish.

You also must set up DNS MX records for the additional domains you want to host. Without those records, servers on the Internet won't know to direct mail for these domains to your Exchange 2000 server. As for SMTP connectors, you can create separate connectors if you want to; the usual reason for creating separate connectors is to set separate policies for mail coming from, or going to, particular destination domains or servers. Separate connectors aren't strictly necessary in this case.