Block an email address at the Exchange server

"To block an email address from being received buy your Exchange server do the following:

1. Open Exchange System Manager
2. In the console tree, click Global Settings.
3. In the details pane, right-click message delivery, and then click properties.
4. Access the sender filtering tab in the message delivery properties dialog box.
5. click add.
6. In the add sender dialog box type the email address which you wish to block then click ok.
7. In the message delivery properties dialog box, select the drop connection if address matches filter check box is selected, and then click ok.
8. In the warning box, click ok to acknowledge that this filter must be enabled on the virtual server.
9. In System manager, go to administrative groups, your admin group, servers, name of your server\protocols\SMTP.

10. Right-click default SMTP virtual server, then click properties.
11. Select the access tab in the default smtp virtual server properties dialog box.
12. Click connection.
13. In the connection dialog box, ensure that all except the list below is selected and then click add.
14. In the computer dialog box, click domain, click ok when warned that this is a resource intensive configuration, type the domain name you wish to block, and then click ok.
15. In the connection dialog box, click ok.
16. Select the general tab in the default smtp virtual server properties dialog box and then click advanced.
17. click edit.
18. In the identification box, select the apply sender filter check box, and click ok.
19. Click ok to close the advanced dialog box.
20. Click ok to close the default smtp virtual server properties dialog box.

The message sender that you block will get a "550 REJECTED" error message from their mail server.