Author: Marilyn Davis Date: To: Marc Sherman CC: exim-users Subject: Re: [exim] Heads up?
On Thu, 24 Mar 2005, Marc Sherman wrote:
> Marilyn Davis wrote:
> >>
> >>>But then, can't we use bounce_message_file to customize the message
> >>>so that it is as friendly as a regular challenge?
> >>
> >>No, because if you're responding with a 5xx to reject the message, you
> >>don't generate any bounce; the _only_ text you get to specify is in the
> >>5xx reason string. If a bounce is generated, it will be generated by
> >>the originating MTA.
>
> Just to follow up on this, I've been experimenting with my own spam
> rejection system today, and discovered that at least Exchange severely
> limits the size of the text it will display in a bounce caused by a 550:
>
> > The following recipient(s) could not be reached:
> >
> > msherman@??? on 3/24/2005 1:47 PM
> >
> > There was a SMTP communication problem with the recipient's email
> > server. Please contact your system administrator.
> >
> > <to-exchsrv-01.fortiva.corp #5.5.0 smtp;550-Spam score too high
> > (996.8). Contact postmaster@??? for>
>
> The error message I sent back ended with " assistance." but that was too
> long. So if you try to implement a c/r system using 550 responses to
> send the challenge, the url to respond to the challenge had better be
> pretty small.
