I have a postfix mail server and want to set quotas in mailboxes and to be dealed with maildrop... I have listened that when is not possible to deliver a message in a mailbox because it's overquota message stays in queue till mailbox has space available or expires in queue... but I don't want this... I want when a message arrives and is not possible to deliver on the mailbox because this is overquota to be bounced back (rejected the message with a bounce) to the sender... and in postfix told me that :

"The sender gets a bounce if and only if maildrop returns a permanent failure code or when it returns a temporary error code long enough for the mail to age out of the queue..."

so how could I obtain that permanent failure code or that temporary error code long enough in maildrop (or how should I configure Maildrop) for causing this bounce with postfix due to maildrop answer?