Redirect Overquota Messages to a Different Account

To redirect a message from its original recipient to another, but only if the account quota was exceeded, perform the following:
 

1. Log into the webadmin interface.
2. Go to the "Security & Filtering" -> "Acceptance & Routing" context.
3. Go to the "Advanced Settings" tab.
4. Click the "Add Acceptance / Routing Rule" button.
5. Enter a descriptive name in the "Rule name" field.
6. From the "Conditions" section, select "Recipient -> Is Overquota".
7. Click "Add condition".
8. From the "Actions" section, select "SMTP->Action"
9. Click "Add action".
10. Set the action "SMTP action" to "Accept" and add an optional message
11.  Again, from the "Actions" section, select "Recipients -> Change Recipient".
12.  Click "Add action".
13. Enter a recipient name and destination folder.
14. Click "Save Configuration".

NOTE: The destination account must exist. If it does not, the redirection will fail and the message will still be discarded.