Re: [exim] Question about forward recipient verify callouts

Marc Perkel wrote:
> I have an unusual situation. I have a customer that I'm spam filtering
> for. Email from the net comes to my servers first, I clean it, and then
> pass it on.
>
> Their server however for some strange reason returns a 450 instead of
> 550 for non-existent users. Text is "User unknown in local recipient
> table". I'm trying to figure out how to capture and test that response
> so I can properly reject this mail rather that retrying for a long time.
>
> Thanks in advance.
>
>

General case is to either shorten all retry timeouts, ELSE put some
logic into place that shortens them for problematic domains.

Anything more 'clever' means you also have to go and kill that message
on the queue.

FWIW - *most* paths are so reliable these days that we don't see a need
to retry for anything like legacy defaults.

If our mail doesn't move within 15-30 minutes, even with the odd
greylist deferral, chances are it won't move in three days either.

Our view is that folks expect 3 to 10 minute transit, so it is better to
let the sender be 'aware' sooner when that breaks so they are not
blindsided, can try again, phone, or fax - as the content may be
time-sensitive.

YMMV,

Bill