>I am using Postfix as an MTA but I see nowadays lot of spam going out of my >system. I have used transport based throttling for a domain but I am looking >for options for per sender based rate limiting. Can I achieve per user based >throttling using postfix or I have to use some 3rd party software ?
>If no what rate limiting software can I use to achieve this. Anything is possible. I'm working on a similar idea for controlling this, where I track the message count over a period of time, for each sender, and if it goes beyond a threshold, they are suspended until it's resolved (or they stop sending). General idea is to catch the SASL sender on before queue, script it against and in memory db (like memcached), and allow/reject based upon throttles setup. If you can write perl/python there are some working samples over on the postfix site that have a base framework for this.
