Setting up the recipient filter is a two step process. Here's how to do it:
This is to fix those queues in exchange form other domains, this is a result of a spam or a invalid email domain and they email to incorrect email name on your system and the postmaster tries to send out to that address to tell it that the email name dosnt exist on your server but because the address the postmaster is sending back to dosnt exist it sits there in the queues.
1. In Exchange System Manager, expand Global Settings, right-click on
Message Delivery, and select Properties.
2. Click the Recipient Filtering tab and enable the "Filter recipients who are not in the Directory" checkbox.
3. Click OK, then click OK on the ESM warning dialog that pops up.
4. In ESM, expand Servers, your server name, Protocols, SMTP, right-click on Default SMTP Virtual Server, and select Properties.
5. In the General tab, click the Advanced button.
6. Click Edit in the Advanced window.
7. Enable the "Apply Recipient Filter" checkbox.
8. Click OK all the way out of the properties boxes.
9. Stop and restart the SMTP service.