[nzlug] (OT) Sorbs etc, was Exim: Limiting outgoing connections on Debian

[Cliff Pratt]

Robin Sheat wrote:
> On Tuesday 10 October 2006 23:30, Simon Lyall wrote:
>> a. Delayed
>> b. Being returned to the sender with an error
>> c. Being lost with no error being generated to sender or receiver.
> Aside from the first one, any remotely compliant sender shouldn't suffer from 
> these. And if it does, then it was likely dropping messages randomly anyway, 
> if the remote host happened to be a little flakey.
>
This assumes that the greylisting server is set up correctly, which 
almost always is not the case.
 >
>> b. Greylisting imposes load on the mail servers of senders.
> Not much of one, provided the greylisting is implemented correctly, and it's 
> only a one off generally.
>
This again assumes that the greylisting server is set up correctly.
 >
>> c. Greylisting is fairly simple for Spammers to beat and they will beat it
>>    when it becomes worthwhile.
> It's not trivial for spammers to beat. Think of sending 100,000 emails from a 
> bot. You're not going to queue them up for retries any time soon. 
> 
Except that these days they use zombies and owned machines. Greylisters 
in general don't use blacklists and hence are open to attack by zombies 
and owned machines.

Cheers,

Cliff