> > If spam filtering (not just RBL, but rules-based filtering) were built
> > into Exim, *and a time penalty were introduced on receipt of a spam*, ie
> > the connection was held open but Exim failed to respond for a long period,
> > might this, if widely used, make it harder for spammers to operate?
>
> This has been thought of before and implemented several times as others
> have answered.
Thanks to everyone for their replies to this. Looks like sa-exim is very
much worth investigating.
One extra point I'd like to emphasise is that if anti-spam measures were
made *standard* in all major mail server packages, then it might have some
impact. Otherwise, piecemeal implementation by particular sites won't have
a big impact on spammers.
