1) How can I limit how many emails per hour each user sends using sendmail. I would like to define that user1 should not be able to send more than 100 emails per hour and user2 more than 10 email per minute. 2) How would you setup so that user1 total email size being sent is less than 1 MB. I think one way to achieve this is to run sendmail in the queue and then create a scheduled script which checks for sizes but i havent tried it. Is there any other way to achieve the same