Depending on the type of messages you are routing, you can create a corresponding address space type. This can be done in the Address Space property page of the connector responsible for routing messages. You can select X.400, Internet (SMTP), Microsoft Mail, or Other.
Depending on the address type you choose, see the appropriate section under "Address Space General Properties" later in this chapter.
For more information about addressing and routing, see Microsoft Exchange Server Concepts and Planning.