I am watching the stinking spammer run his puny dictionary attack on one of our hosted main sites slowly whole day. There is an option for the non-existent account attempts to delay the delivery after xx seconds, and it works. In the whole day, he managed to try maybe 8-10 names from his dictionary.
However... is there a possibility or an add-on to ban the IP attempting such actions after X attempts for X seconds/minutes?
Thanks, I was just browsing greylisting.org planning to implement grey- and whitelisting. Postfix has a somewhat simplified greylisting ability built in (not on by default though) so I was looking at it, but I will surely look into the script you posted me.
And as whitelisting is strongly adviced with greylisting, would this list: