On 10/23/06 11:56 PM, "Johann Spies" <jspies@???> wrote:
> I have not implemented greylisting so far. Maybe it is time to do so. I
> am not quite convinced that it is an unmixed blessing. Can somebody
> convince me?
It is helpful, but you MUST whitelist sensibly. There are at least three
classes of things in "sensibly"
1. neighbor ISPs and others that routinely send mail to your users but are
not "large and well known".
2. large and well known senders which will pass greylisting anyhow even
though spam comes from them (eg hotmail)
3. broken sending servers (there is a nice list available somewhere on the
www.greylisting.org site that will serve as a starting point).
We have just under 700 entries in our whitelist database table.
All that said, the engine sending the image spam (or at least one) passes
greylisting, so greylisting won't help with it. (This is likely the
beginning of the end of greylisting as a helpful technique.)
--John
