Local domain: All of your Exchange 2000 servers accept messages for all domains listed in all Recipient Policies. Start by creating a Recipient Policy that includes SMTP:@domain (e.g., SMTP:@tntsoftware.com) for the address. Check the checkbox for the SMTP domain and the checkbox for "This Exchange Organization is responsible for all mail delivery to this address." See How to: Configure recipient policies in Exchange 2000 Server for information on creating Recipient Policies. Additional information can be found by reading How to receive messages for two SMTP domains using Exchange 2000.
Non-local domain: Non-local domains are also called relay domains. An example of a non-local domain would be the pre-existing domain for a recently acquired company. Another example would be if your company underwent an organizational name change. Start by creating an SMTP connector to the non-local domain. When you do this, check the "Allow messages to be relayed to this domain" checkbox on the Address Space tab on the Properties dialog for the SMTP connector. Note that the specified source bridgehead server(s) will be the servers that accept messages for this domain. See How to configure the SMTP connector in Exchange 2000 for details on how to configure an SMTP connector.
Shared domain: If you are sharing a domain with another SMTP server and you want Exchange 2000 to receive messages for that domain, you setup an SMTP connector for this domain. Then add the domain to your Recipient Policies, making sure that the checkbox for "This Exchange Organization is responsible for all mail delivery to this address" is not checked.
For more information, see Sharing SMTP address spaces in Exchange 2000.
This was first published in March 2003