Josip Rodin wrote:
> On Wed, Nov 29, 2006 at 11:42:10AM -0500, Dean Brooks wrote:
>
>> Keep in mind that there *are* sites out there that:
>>
>> - Dont ever retry at all
>> - Retry only once after one hour
>> - Retry once only every 24 hours
>> - Treat temporary errors as failures
>> - etc.
>>
>
> I recently encountered one ISP which retries in fifteen minute intervals,
> but only three times, before it gives up. Wackos.
>
>
And therein lies the rub. I think the solution is to apply greylisting
selectively rather that to everyone. Suppose that you only applied
greylisting to hosts that:
Have bad RDNS
In home/dynamic IP ranges
Fail and header test
Has any slightly weird HELO
Mail From:<>
Listed in Blacklists like Spamcop that are not good enough to block on
What that you will probably block almost as much spam without the delays.
