On Fri, 10 Oct 2008, Greg Hewgill wrote:
Have you considered assigning reputation to nameservers? I've thought
I think that simply inserting pseudo headers like:
X-NameServer: ns39.domaincontrol.com
X-NameServer: ns40.domaincontrol.com
Into the message fed to bayesian content filtering would do the trick. Mail
from spammer nameservers will make it past SMTP envelope, but should
end up in quarantine - and each days batch of domains should get blocked
in SMTP envelope after 20 quarantined spams each.
Looking up multiple reputations in MFROM could be a problem - some of
my systems get 400000+ connections a day, and I depend on rejecting
efficiently in envelope.
If I was going to do complex processing at envelope, I would feed everything
known so far about the sender: MXs, NSs, As, PTRs, HELO, MFROM, RCPT, even hour
of day (I've noticed spam tends to prefers certain time slots) to a bayesian
filter.
--
Stuart D. Gathman <stuart(_at_)bmsi(_dot_)com>
Business Management Systems Inc. Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flammis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.
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