Author: Christoph Kliemt Date: To: exim-users Subject: Re: [Exim] Greylisting + multiple MX hosts -> multiple attempts
Alun <auj@???> writes:
> Fred Viles (fv+exim@???) decreed:
>>
>> I'm not so sure it is a valid assumption, however. I think normal MTA
>> queue management and retry behavior would indeed be very burdensome
>> for the spammers, but ISTM dedicated spamware wouldn't need to do
>> that. A technique like simply running through their address list
>> twice in two hour chunks would do the job.
>
> I suspect that this will come. That's why I'm thinking about variable
> delays here. If they want to get a pile of addresses through the
> greylist at any sane sort of speed, they've got to have a pile of
> attempts in the "grey" state. If we can find any way of tying those
> attempts together (e.g. by source IP address, we can penalise them by
> upping the delay time).
Yes, this is a possibility. The question is how. Smaller peer-to-peer
networks that interchange these data? Or abuse DNS in RBL-style again?
Or.. other ideas?
