Re: FW: Problems with bad header 'from'

[Matti Aarnio <mea@nic.funet.fi>]

On Wed, Jun 25, 2003 at 12:08:18PM +0200, Marek Kowal wrote:
> This is a topic from a year ago... but needs refreshing. Specifically, how
> can I bounce the message (where in router and how?), that does not contain
> @domain in From: field? I see more and more such messages coming to my site.

Adding/writing more full-fledged header parser in the smtp-contentfilter
would be the right place to do that, I think.  Inside the system
I do often send email as:
    From: Matti Aarnio <mea>
which the router will then qualify for outgoing:
    From: Matti Aarnio <mea@nic.funet.fi>

That  smtp-contentfilter now supplied in the system has been intended
only for showing the interface functionality, and give some ideas of
how to make it in e.g. C ...  but I do run it in quite heavy load
systems as is..  Perhaps I should at least do perl pre-compile for
those uses..

For spam flighting there are usually better indications, than possible
disagreenments in headers. (E.g. a lengthy message written in all
capitals is likely spam...)

> Cheers,
> Marek
> 
> ps. Do you see such behaviour as well? If so, how do _you_ handle it?

  Usually I just ignore it.

> > -----Original Message-----
> > From: Arnt Gulbrandsen [mailto:arnt@gulbrandsen.priv.no] 
> > Sent: 8 sierpnia 2002 15:00
> > To: Bartosz Klimek
> > Cc: zmailer@nic.funet.fi
> > Subject: Re: Problems with bad header 'from'
> > 
> > 
> > Bartosz Klimek <bartoszk@onet.pl>
> > > While it seems to be a correct behaviour, it is very 
> > problematic for our
> > > employees. Is there an easy way to make the router to 
> > replace the invalid
> > > 'from' field with the 'from' e-mail address from the envelope?
> > 
> > Not that I know about. However, I would be very cautious 
> > about doing that.
> > 
> > Suppose that the From field is illegal, and that the envelope from and
> > the Reply-To field differ. What should the router do? (Yes, I've seen
> > cases where both would be the "right" choice.)
> > 
> > Or even better: There's a Sender field, and it too is different. What
> > should the router guess?
> > 
> > My personal choice would probably be to bounce the message. 
> > If you can't
> > deal with a message reasonably, an error message for the sender is a
> > respectable solution.
> > 
> > --Arnt
-- 
/Matti Aarnio	<mea@nic.funet.fi>
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