Hey Todd,
thank for your answer. Do you have any ideas how can it be done? What rules
must I use somwhere in exim4 for this to work?
The Exchange autoresponder replies only once to any e-mail so I probably am
safe regarding the routing problems..
BR,
Uros
2011/3/7 Todd Lyons <tlyons@???>
> On Mon, Mar 7, 2011 at 4:19 AM, Uros Meglic <uros.meglic@???> wrote:
> > What I'm trying to do, is to rewrite the "Return-Path:" on my Exim4 smtp
> > relay server. The server accepts mail from an Exchange 2007 server and
> > relays it to the internet via ISP smarthost. The reason I'm trying to
> > rewrite this specific header is, that per some RFC Exchange is creating
> > automated out of office e-mail responses with this header present, but
> not
> > populated, so it looks like this "Return-Path:<>". Our ISP smarthost
> doesn't
> > accept any e-mail messages if the Return-Path is empty. I can't set
> Exchange
> > to deliver via DNS.
>
> It can be done, however I would strongly advise against it because you
> are opening yourself up to some pretty severe routing loops. The RFC
> they're referring to is:
>
> http://tools.ietf.org/html/rfc3834
>
> The autoresponder should not reply to any email that "has a
> Return-Path address of <>". This means that if you change your return
> path to non-null, and your autoresponder sends an email to a lesser
> quality autoresponder, then that one will reply to yours, then yours
> will reply to that one (AGAIN), then that one will reply to yours
> (AGAIN), and repeat ad nauseum until yours or his bandwidth and load
> spike or customer complaints or yours or his harddrive fills up.
>
> Your ISP undoubtedly has been hit very hard with spams that were sent
> to <> and so they just stop accepting it. But that's not a get
> netizen. But then again. I don't know the extent of the problems they
> were dealing with. But even so, the RFC's do say that you must accept
> mail to <> (but I do still filter the crap out of it).
>
> In the end, there are good points on both sides, but your ISP is
> making your life difficult when it seems like they shouldn't.
> --
> Regards... Todd
> I seek the truth...it is only persistence in self-delusion and
> ignorance that does harm. -- Marcus Aurealius
>
