Remote check for over-quota condition of the mailbox
At least while migrating, and perhaps afterwards, our system utilizes a relay based on sendmail which trims a lot of spam based on simple rules (milter-greylist, milter-regex, banner delay, DNS RBL) and passes the rest to an internal system (some domais go to specific boxes and mostly to our old mail server, now the new Sun MS).
After implementing Sun JES infrastructure, LDAP in particular, we added LDAP routing to sendmail so that the relay knows which usernames exist - and this tremendously decreased bounce letters due to spam for inexistent recipients (now the error is returned within SMTP dialog of spammer to relay).
However I can imagine that when some users' boxes climb over quota and perhaps exceed grace time so their mails won't even be queued by Sun MS, we'll again have a flow of bounces from Sun MS to spam senders.
The question is: Is there some LDAP flag-attribute that is set for overquota boxes, so our relay can take that into account?
I think it is easily possible to craft one if it does not exist now (i.e. with a cron script), but perhaps I'd reinvent the wheel? (Again!?)