Re: [exim] Greylist -Hosts sending from Multiple MX's.

On Tue, Aug 26, 2008 at 11:17 PM, Grant Peel <gpeel@???> wrote:
> Hi all,
>
> A few months back, with alot of help from this list, I implimented
> GREYLISTING (which is working well), with one exception:
>
> Some ISPs (mail hosting farms, Spam scanning services etc, sometimes resend
> from a different MX each retry period, which, obviously, causes some serious
> email delays - todays for example, was delayed about 8 hours.
>

We observe good results by using the combination of

${mask:$sender_host_address/24}
${lc:$sender_address_domain}
$local_part@$domain

as the primary key for greylisting lookup.

Of course this does not help if the sending hosts are distributed
across multiple C-class subnets.

Chris