[Greylist-users] Microsoft and Greylisting

[Franck Arnaud]

Sam Kalet:

> [www.spamsquelcher.com]
> I haven't come across an open source implementation of this 
> type of approach.

Regular firewall stuff should be usable (iptables --limit 
seems appropriate).

To trigger it, you could either have static rules (updated 
daily or weekly say) based, for instance, on an aggressive 
blacklist (one that is not usable for plain blacklisting) 
you can download, or otherwise combine it with a log 
analyser that checks port 25 traffic very often and adds 
limit rules for anyone DNS blacklisted that talks to you. 
This should achieve something very similar to 
spamsquelcher.com.