send mail limit per day

i would like to suggest directadmin can publish a function which can allow us to set user limit on the number of email to send out daily.

this can help us to prevent mail spamming from the server.

so far i have been face this problem always when user send out mail in bulk and cause server down.

There is a plugin from my compatriot: http://directadmin.com/forum/showthread.php?t=8393