The Recipient Blacklist allows you blacklist emails sent to specific local email addresses or domains.
The list is available under in the left navigation pane.
You can enable or disable the Recipient Blacklist test by clicking the ON / OFF button on top of the page, or on the page.
Select the "Blacklist only the list below" option if you want to blacklist those emails only that have been sent to recipients on the list. If you want to blacklist every email, except those that have been sent to recipients on the recipient blacklist, select "Blacklist all addresses, except the list below". This later option is useful when you cannot use the Recipient Validation Test, but you want to blacklist emails addressed to non-existent local addresses.
Click the New button to add an email address or email address expression to the list. To modify an existing email address expression, click Modify or hit Enter. Email address expressions can be deleted using the Delete button or the Delete key.
Click the column header of any column by which you wish to sort the Recipient Blacklist. To reverse sorting, click the column header again.
Right-click on the list and select "Import list..." or "Export list...". Alternatively, you can do this from the menu, select or and select the list you wish to export / import (inclusion or exclusion list).
For more information about various formats supported, see the List Import and Export Formats section.
At the Before Arrival filtering point, the recipient blacklist hit causes recipient rejection, so the blacklisted recipient does not get the email.
The On Arrival actions does not apply to the recipient blacklist, because the goal of this list is to block emails sent to non-existent local mailboxes. When the email has only a single recipient, it gets rejected (because there are no valid recipients). If the email has multiple recipients and only some of the recipients are blacklisted, the blacklisted recipients are removed from the recipient list, but the remaining valid recipients still get the email.
Email blacklisted by the recipient blacklist at the Before Arrival filtering point get rejected with an SMTP response indicating a protocol error. Edit the SMTP response for the recipient blacklist on the page (click Edit under Before Arrival).
Email servers generate a bounce report (NDR) if they cannot deliver the email to the recipient due to a protocol error. Most email servers include the SMTP response of the recipient email server in the report, so you can customize the information received by the sender by editing the SMTP response.
If you cannot use the Recipient Validation Test, you can switch the Recipient Blacklist to "Blacklist all addresses, except the list below" and add list the valid addresses of your domain. Every email addressed to recipients that are not present on this list will be rejected.