How to Configure a Connection Filtering Rule
Connection filtering blocks messages based on the Internet Protocol (IP) address of the connecting SMTP server. You can subscribe to a third-party block list provider and configure a connection filtering rule that checks against the provider's list of specific IP addresses. Specific configuration of connection filtering rules is dependent upon the block list provider. This procedure outlines how you can configure a connection filtering rule.
Procedure
To configure a connection filtering rule
On the Connection Filtering tab (see the following figure) of the Message Delivery Properties dialog box, under Block List Service Configuration, click Add.
Connection Filtering tab in the Message Delivery Properties dialog box
For More Information
For more information about connection filtering and how it works, see "Connection Filtering" in What's New in Exchange Server 2003.