Milter-greylist

Oliver Fromme <olli@...> wrote:

> In order to change even a single pixel, the spammer would
> have to decompress the image, and then compress it again.
> That costs quite a bit of CPU resources, so I don't think
> they're doing that when sending millions of spam mails.

I suspect they just build the image on the fly when sending spam. That
costs nearly nothing.
 
> It might work on personal machines that receive only mail
> for one person, or maybe a few users.  (Obviously that's
> already the case, see SpamAssassin + gocr.)  But it won't
> work on large servers that receive mail (and spam) for
> hundreds or thousands of people.

It's easy to scatter the job on several machines...

-- 
Emmanuel Dreyfus
http://hcpnet.free.fr/pubz
manu@...