How to Stop External Spoofed Mail From Your Domain

Email spoofing is a phenomenon where you receive a large number of non-delivery reports for emails that you never sent. These e-mails tend to have been sent from your domain name. This typically occurs when a third-party hacks or "spoofs" into your email account and starts sending messages. The best way to stop external email spoofing from your domain is by disabling your catch-all email address. A catch-all email account is a mailbox on your domain that catches all emails addressed to the domain that do not exist in the mail server.

Instructions

1. Log in to your computer using your administrator's user name and password.

2. Click the Start menu and select "All Programs." Click "Microsoft Exchange Server." Click to open "Exchange System Manager."

3. Double-click to expand the root menu in the left pane. Locate "Message Delivery."

4. Right-click "Message Delivery" and select "Properties."

5. Click the tab "Recipient Filtering."

6. Click to clear the check mark next to "Filter Recipients who are not in the directory."

7. Click "Apply." Click "OK."

References

• Exchange Sembee: Filter Email for Unknown Users
• Ecenica: What is E-mail Spoofing?
• Halon: Mail Gateway Recipient Filtering