I see what your saying but I want the sender to know the message was not delivered. Bouncing junkmail to over quota accounts can get you blacklisted but rejecting will not. If we had a list of email accounts say 90 percent full we could do something like this.
deny recipients = lsearch;/etc/virtual/over_quota
message = This email account is over quota. Mailbox is FULL
Something like this would give them that error message like this:
*****************
Delivery to the following recipient failed permanently:
*****@******.net
Technical details of permanent failure:
******** tried to deliver your message, but it was rejected by the server for the recipient domain ***********.net by mail.*********.net. [*.*.*.*].
The error that the other server returned was:
550 This email account is over quota. Mailbox is FULL
*****************
A reject message is very likely to make it through the senders spam filters since its from the senders MTA. A bounce not as likely.
The problem with this method here even if we had a list of over quota accounts is that forwarders do not work with it very well but I imagine that would be same with the default bounce.