[not entirely OT, but leaving the subject unchanged]
On Sunday 04 December 2011 04:59:45 Steve wrote:
> > Von: Steve Fatula <compconsult...@yahoo.com>
> > >I wish there was a chart for spam sent FROM yahoo. 99% of
> > >our spam comes from yahoo (that gets through postscreen).
>
> On my end it is hotmail. Anyway.... postscreen is as good as you
> configure and use it. There is IMHO no universal valid conclusion
> about quality when you write "that goes through postscreen".
The point about "gets through postscreen" probably was that it's not
safe nor easy to try to block spammer-controlled freemail accounts
through postscreen. In postscreen, there is no difference between
freemail spam and real mail from freemail users.
The only reasonable pre-DATA approach to freemail-origin spam is to
use check_sender_access in smtpd against a list of known bad accounts.
Creation and maintenance of such a list would be a very big chore.
ISTR someone having attempted to publish a list like this, but it is
certain to be far from complete, as spammers are signing up new
accounts and compromising existing credentials all the time. It's
likewise sure to be a high-maintenance task, since when people find
that their freemail account has been cracked, they are likely to
change the password and thus at least temporarily stop the abuse.
> IMHO there is a reason for content filters. They are able to catch
> those remaining messages passing such filter types like
> postscreen. From the viewpoint of such filters (like postscreen)
> the mail coming from yahoo (or in my case hotmail) are legitimate
> since they are coming from the proper sources, obey EHLO/HELO
> delays, are often digitally signed, are in no blacklist, etc...
Exactly the point the other Steve was making.
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