Re: [Exim] Delay 220 greeting to reduce spam?

On Tue, Jun 01, 2004 at 07:23:34PM -0500, Mike Bacher said:
> Is there a way to make exim delay giving the initial 220 greeting for an
> arbitrary amount of time (say, 40 seconds or so)? The idea is that most
> spamware will give up after 30 seconds (most are quite impatient from
> what I've read) and move on to the next host. Others that have
> implemented it on their MTAs have seen good results with this method.

You are going to find some ISP's who deal with huge volumes of mail have
short timeouts in a lame attempt to reduce server load. One nameless ISP
I deal with on a regular basis has a 30 second timeout. Even worse, when
sending them mail, you only have 30 seconds between initial connect and
DATA to start sending before they puke (and they just happen to slow you
down doing callout sender verification too.) Horrible.

You may find that you need to whitelist certain hosts - possibly with a
greylisting type DB. In fact, greylisting may be a better solution for
you (google: greylisting exim)