Re: More sorbs blacklisting
On Mon, 31 Jul 2006 18:42:17 +0200, Michelle Konzack
<linux4michelle@freenet.de> wrote:
>> Why worry about missing "legit" mail?
> I get per day between 500 and 8000 Spams against 1500
> messages "legit" per day on my E-Mail and catch over
> 99% of them with less then 99,9% FalsePositive.
How do you know what your false positive rate is, unless you review
each spam? Do look at 8000 spams each day, just to see if one might
be a false positive? Personally, I wouldn't do it.
I can't specify exactly what my false positive rate is, but periodic
review of my mail logs indicates that it's not enough to worry about.
With DNS checks, dynamic/dialup regexes, and a few good dnsbls, spam
content filters are unnecessary. The DNS checks alone catch 60% + of
the spam hitting my mail server, and that's why DNS is my first test.
DNS is like auto registration. An honest citizen would not operate
their car on the highway without a valid registration. So why would
anyone expect to send email without proper DNS? Of course spammers
do, and since no honest emailer wants to look like a spammer, having
matching forward and reverse DNS is like having an auto registration.
It's such an easy check to do, and it catches so much spam, it should
be the de facto standard for email.
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