Re: [Exim] Mail Loop with Null Senders and Oracle WorkFlow

On Sat, 31 Jan 2004 17:01:09 -0700 (MST) Kevin wrote:

[preventing mail loops caused by stupid software]
> Tim Jackson wrote:
> > [suggestion to] use a system filter to insert a unique
> > "token" header (e.g. "X-Flooble: Anti-loop") into locally-generated or
> > received bounces, and then again with the system filter (before the
> > addition of the header) check for that "token" in the message body of
> > received/generated bounces - if it exists, assume it's a loop and
> > devnull it. ...
> I thought of doing something like that... but I'm not sure that will
> work.
> I don't think you will get back the same headers especially on those
> systems that accept the message and bounce back a different message.

You're entirely right - it won't work in all circumstances. It will at
least help though. It should work in any circumstances where a remote host
1 hop from the mailhub rejects at SMTP time, since Exim will generate a
bounce which includes the headers. And of course with any remote host
generating a bounce which includes the full headers. But yes, some kinds
of bounces, vacations/OOO replies etc. would be missed. Although in the
case of vacations/OOO's, they *should* break the loop themselves by
refusing to keep sending messages to the same address multiple times in
close succession.


Tim