Lyris automatically tracks how many messages per day are sent From a foreign address to a Lyris address, and if the number of messages in one day exceeds the Loop Detection threshold,
Lyris cuts off the mailings, issuing a single refusal message, and then discarding the rest of the messages in that 24 hour period.
This feature is useful for automatically breaking mail loops that aren't able to be stopped through Lyris' other mechanism, and also for stopping a mail bomb attack. Say, for example, that someone
sets their email program to send thousands of messages to your autoresponder, in order to mail bomb you, and tie up your server, this feature will detect this, notify the administrator and
automatically stop the process.
Note: some sites use a Web CGI script to sign people up to their list. In such a case, the script might be sending from the same address every time, and to the same address every time, and thus be
perceived as a mail loop, if the quantity of mailings goes over the loop detection threshold. In such a case, you should put an exception for that specific from/to combination to exempt your script
from this test. If you forget to do this, the server admin will receive notification of the potential loop, and you'll thus be reminded of the need for an exception.