Re: Thoughts based on two recent threads (Greylist and DBL).

Ralf Hildebrandt wrote:
> * Matt Fretwell <mattf@bauchan.org>:
>
>
>>Dynamic != spam. There are plenty of legitimate dynamic clients/servers.
>
>
> Unfortunately, there are many zombies there as well.
>


true enough, but blocking dyn ip brings its own problems.

As this thread started, using GL (maybe coupled with other tests) is
possibly a way to distinguish zombies from MTAs.

one other test that can be added is to resolve the helo, i.e. if this
resolves to the client IP (but doesn't seem dynamic), chances are the
client isn't a zombie. or will spammers register as many domains as
there are zombies? probably not.