I am running a small server on a LAN and do not expect more than a couple dozen emails an hour or so. A user on the LAN accidentally set off a few thousand emails at once. Is there a tool or setting (using exim4, but any popular open source MTA available on Ubuntu will do) that could temporarily block such episodes or at least send a notification so that the excitement can be contained?
Nothing came up in a quick search, so even useful search terms would be helpful as an answer.
