SMTP Rate Limiting

Is there a way in Virtualmin to limit how many messages users can send? I was thinking like 500 emails a day or an hour or something.



You can setup some generic rate limiting in Postfix, but there aren't any per-user settings.

Something like "smtp_destination_rate_delay" can rate limit how many messages go to a given host within. The setting for "smtp_destination_rate_delay" defines how many seconds Postfix will wait before performing a delivery to the same SMTP desatination (ie, to Hotmail or Gmail).

Details on that are here:

How would I go about limiting how many emails a user or a domain can send per a given time frame. Is that something I would have to do with policyd or postfwd?

I don't know how to setup what you're describing within Postfix. Some posts I'm reading suggest it's not possible. It's at the very least difficult :-)

So you may need to introduce a new tool into the mix, such as one of the two you mentioned.