Just sharing some ideas on blocking outbound spam. Maybe these ideas
will make it to the big freemail companies because most of the spam that
manages to get through my filters comes from AOL, Gmail, Yahoo, and Hotmail.
I've found outbound spam filtering to be very different than inbound
filtering. And I've been reasonably successful in stopping spam that I'm
filtering for other people's outgoing servers. Here's the core of how I
do it.
First - spammers never send spam slowly. So if the account is sending
email slowly then I don't have to look at it. So it just passes.
When email is coming fast from an account I start tracking the number of
bad recipients and if the number of bad recipients is high it's probably
spam.
I also have restrictions on valid domains the from has to match, I look
for URIBLs, high SA scores, etc.
Just curious what others do to detect outgoing spam.
I use Exim for the MTA because it has the power to do the tricks I need
done.
--
Marc Perkel - Sales/Support
supp...@junkemailfilter.com
http://www.junkemailfilter.com
Junk Email Filter dot com
415-992-3400
