[Test-Equipment] About spam filtering -- way off-topic (was: Re: dismantling my repair lab ...)

[Mike Andrews]

On Sat, Apr 07, 2012 at 11:17:39PM -0400, Ron Youvan wrote:
>    Pete M wrote:
> 
> > *********************************************************
> >          SPAM
> > *********************************************************
> > The ISP has determined that this email contains SPAM
> 
> 
> > On 4/7/2012 6:30 PM, Bryan Campbell wrote:
> >> Two labs; rough life!
> 
>    How in the world could an ISP determine what is SPAM and what is not?
> SPAM is not a computer component, it is UNWANTED advertizement, how can an ISP figure that out and 
> what business is it of theirs?

It's what I do in the dayjob. 

The definition of spam that most conscientious providers use isn't
"unwanted advertisement", but rather "unsolicited bulk advertisement".

Since some providers are bad neighbors who don't monitor their complaints
queues for spam complaints and take action on the senders, it falls to the
receiving providers to monitor and filter their inbound mail for spam, and
at least mark it so that the user can avoid it.

Filtering an inbound mail feed is more an art than a science. It is
horribly complex, difficult, inexact and failure-prone. It risks false
positives, which filter good mail as spam, and false negatives, which are
analogous to polluting drinking water with sewage.

In the instant case, the provider's spam filter misfired with a false
positive, but marked it, rather than sending it to data heaven.

Here endeth the lesson.

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin