[Mimedefang] OT: DNS sanity check
John Rudd
john at rudd.cc
Thu Jul 5 15:01:23 EDT 2007
Jeff Rife wrote:
> On 4 Jul 2007 at 20:18, John Rudd wrote:
>> The false positive rate isn't based solely on rejections, it's based on
>> things which triggered the Botnet rule.
>
> You misunderstand.
>
> Look at the messages that are being rejected solely because of the
> extra 5 points you score for bad DNS. I'm willing to bet that this is
> a very small number of messages.
It's not. Further, it means that the message had to be both spammy
enough to score a 5 on its own, AND come from a host with poorly managed
DNS. That really does narrow down the field.
> Second, it's very likely that that in that small number of messages,
> the the number of false positives is rather high, simply because the
> total number of messages is small and the primary reason for rejection
> has a *huge* false positive rate.
I can't speak for the internet as a whole, but it does NOT have a huge
false positive rate. It has a _tiny_ false positive rate. Most
legitimate outbound email servers do appear to have their DNS properly
configured. The ones who don't actually appear to be a small minority
(from where I sit, and from where most of the users of my plugin report).
More information about the MIMEDefang
mailing list