On 26 September 2007, Craig Skinner <[EMAIL PROTECTED]> wrote:
> RW wrote:
> >
> > What I was getting looked like backscatter and smelled like backscatter
> > it is just that some of the IPs sending it didn't check out as MTAs.
> > i.e. they were not listed MXs for the domain they came from AND the
> > domain was not likely someone with separate outbound senders.
> >
> > They all retried too and when I had them as TRAPPED entries the logged
> > data included typical failed-to-deliver messages.
> >
>
> 'bots getting smart eh? Bugger! If that is the trend, greylisting starts
> to lose its value as spammers adapt to the RFCs.
[...]
Greylisting is trivial to bypass, with or without a queue: just send
the same messages twice. Some spammers have figured that out long ago.
Ever wondered why sometimes you receive 2 or 3 copies of the same spam,
from the same IP, with the same Message-Id etc., a few minutes apart?
Regards,
Liviu Daia
--
Dr. Liviu Daia http://www.imar.ro/~daia
