In our university, there are always students who fall for phishing mails. Very often this happens over the weekend and then several thousand mails will be sent through our mail servers. If we are lucky we do not get blocked by any blacklist.
We either need an alerting system or a possibility to block spammers. I would prefer if the spamming user is locked after a certain number of sent mails until I unlock the user again. Instead the user is locked by rate control for 30 minutes.
Such a solution is very important for us, because if we continue to get blocked by blacklists I am forced to look for another anti spam solution.