On Saturday, April 2, 2005, 4:09:31 PM, Jay wrote:

JSHNL> Hello - 
 
JSHNL> I am reviewing your MDLP report at
JSHNL> http://www.sortmonster.com/MDLP/MDLP-Example-Long.html, and find some
JSHNL> tests that are seemingly quite effective that I'm not familiar with.  If
JSHNL> anyone has any informaiton about these tests, please let me know:

JSHNL> - FABEL (is this the same as FABELSOURCES at
JSHNL> http://www.declude.com/Articles.asp?ID=97&Redirected=Y?)

FABEL           ip4r    spamsources.fabel.dk            127.0.0.2

JSHNL> - MXRATE-*

MXRATE-BLACK    ip4r    pub.mxrate.net                  127.0.0.2
MXRATE-WHITE    ip4r    pub.mxrate.net                  127.0.0.3
MXRATE-SUSP     ip4r    pub.mxrate.net                  127.0.0.4

JSHNL> - UCEPROTEC*

UCEPROTECRDO    ip4r    dnsbl-1.uceprotect.net          127.0.0.2
UCEPROTECCMUL   ip4r    dnsbl-2.uceprotect.net          127.0.0.2
UCEPROTECCVIR   ip4r    dnsbl-3.uceprotect.net          127.0.0.2

JSHNL> Also, perhaps I am misunderstanding the data, but SNIFFER has a SQ of
JSHNL> .802 - isn't that relatively "bad" ?

Actually, that's the hyper-accuracy penalty at work. I wrote a bunch
about that on the MDLP page. What's going on is that SNF frequently
catches spam that virtually no other tests are catching yet and as a
result the total weight never reaches the threshold. Every one of
those events shows up counting against it.

We research these periodically (we used to look at them constantly)
and with very rare exceptions we find that these are not false
positives.

In fact, on our systems last year SNF had fewer than 10 FP. (several
of those were messages from customers that actually contained examples
of spam, malware, or logs with spammy URI). Of course, our numbers are
a more than bit skewed because the vast majority of traffic on our
system is spam... so we can't use that to calculate a "false positive
rate" that has any real meaning.

The closest we can really get to an indication of false positive rates
from SNF is to point at our FP rate page:

http://www.sortmonster.com/MessageSniffer/Performance/FalseReportsRates.jsp

This page shows counts of all false positives reported to us on a
daily basis for all of our customers. At least two of these systems
are service providers with 10 or more licenses which submit false
positives automatically as they are reported from their customers.

So anyway, the short answer is that the SA and SQ values on the
SNIFFER tests are skewed by the hyper-accuracy penalty inherent in how
MDLP develops these scores. The true accuracy values are very much
higher and this is regularly confirmed by both hard reviews of the
data and anecdotal evidence from our customers.

Hope this helps,

_M




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