Time-Out ability?

[Aaron Abramson]

Is it possible to configure postfix with a threshold where if a  
certain user or IP address sends 1000 emails or more in an hour, they  
are blocked from sending email for a period of time?

We occasionally have users on our network with infected machines, or  
perhaps they are actually spammers...  and I'd like a mechanism by  
which a "power user" can get put into "time out"... and then re-enable  
access after a period of time.


(We manage a network of wi-fi hotpsots around the country, so blocking  
an IP would block smtp access for all of the users at that hotspot,  
thus the automatic re-enabling of access after 30mins or so).


Thanks,
~Aaron