On Mon, 2004-02-02 at 12:03, Dennis Davis wrote:
> >From: Martin Evans <m.d.t.evans@???>
> >Subject: [Exim] spam delay trick and smtp_accept_count patch.
> >To: exim-users@???
> >Date: Mon, 02 Feb 2004 11:47:31 +0000
> >
> >An anti-spam trick was suggested to me a few weeks ago by a colleague in
> >our university. The idea is that we add longish delays into the smtp
> >conversation if we suspect that the sender is a spammer. i.e. if the
> >sender is on an RBL list we add an acl like:
> >
> >accept dnslists = rbl-plus.mail-abuse.ja.net
> > delay = 1m
> >
> >My colleague has reported that this trick is successful at reducing the
> >amount of spam he sees being delivered into his department.
> >
> >However, I am concerned that my process tables will fill up with RBL'ed
> >hosts connecting to my server and filling up my (smtp_accept_max)
> >connections. So, I'd like to defer RBL'ed hosts at a lower limit (to get
> >rid of their connections). A one line patch makes the number of
> >connections available in the ACLs. Note patch is against exim-4.14 (or
> >maybe 4-20):
>
> Why not just use smtp_accept_max_per_host? It's an expandable
> string if you want to get creative. This main configuration
> variable was there in exim3, so it's always been usable in exim4.
Because the exim4 ACL variables are not available in the main body of
the configuration... or at least they were not last time I looked. Also,
I've already expanded it (for other reasons) and am a bit worried it
might get too messy. I think it is neater to do this in the ACLs.
Martin.
--
-- Dr MDT Evans, Computing Services, Queen Mary, University of London
