Author: Alan J. Flavell Date: To: Exim users list Subject: Re: [Exim] Sender verification... long-term temporary failures should
be considered permanent.
On Thu, 30 Oct 2003, David Woodhouse wrote:
> On Thu, 2003-10-30 at 18:51 +0000, Alan J. Flavell wrote:
> > I've no expertise with intermittently-connected MTAs, [...]
> It's Demon Internet's mail host -- it'll try sending mail by SMTP
> whenever I reconnect (and some other times besides although
> bizarrely not when I ETRN) and will keep it for a _long_ time
> without bouncing it. It's _designed_ for intermittent connections.
Hence my disclaimer ;-)
> Yes. As far as I can tell it _does_ do a fresh callout every time.
AIUI, exim sees no need to remember that the previous attempt gave a
temporary failure. It just does a fresh callout.
> > Usually, a solution to this kind of requirement would be a little
> > Perl script - invoked via ${run...} if you haven't got the Perl
> > scripting interface in your exim build.
>
> I could indeed do it with an external database, but that seems a little
> strange since Exim already does almost every part of what's required;
You'd be making use of exim's callout mechanism anyway; but AFAICS
you're going to have to keep a tally on the results for yourself.
> logging the results of callouts into a database, with timestamps etc.
Take a look in that data base, then, with something like (in our
case):
/usr/sbin/exim_dumpdb /var/exim/spool callout | more
You'll see that the cached results of callout are either 'accept' or
'reject' - never 'temporary fail'. Unless someone's looked into the
code and knows something that isn't shown here, I don't think you will
find the specific data that you need for running your plan. Sorry...
BTW, don't entirely forget that a bona fide sender _could_ be out of
contact for several days in adverse situations.
