You need to create a new SMTP Connector.
Open the Exchange System Manager (Exchange System Manager.msc).
Ensure that you have enabled viewing of administrative and routing groups (see Recipe 7.3).
Expand the organization→ Administrative Groups→ target administrative group→ Routing Groups→ target routing group.
Right-click the Connectors container and select New→ SMTP Connector.
On the General tab, enter a name for the connector.
If this connector should forward all outbound traffic to a smart host, select Forward all mail through this connector to the following smart hosts and enter either the IP address or fully-qualified domain name of the smart host. IP addresses must be in brackets. You can include multiple values by separating them with commas or semicolons.
Click Add and add at least one virtual server as a local bridgehead.
On the Address Space tab, click Add, select the address type from the list (usually SMTP), and click OK. Enter the domain name for the address space and the routing cost for this connector. A domain name of * matches all domains. Click OK.
Select the scope for this connector: Entire organization or Routing group.
Click OK to create the new connector with default settings. If you wish to change these defaults, right-click the new connector object, select Properties, and make your desired changes.
The Exchange 2000 SMTP implementation provided a large improvement over the Internet ...