On Thu, 8 May 2003, Tony Finch wrote:
> It does actually -- the table in section 3.6 says:
>
> Field Min number Max number Notes
>
> resent-to 0 unlimited* One per block - see
> 3.6.6
So it does! That hadn't penetrated my brain. So we just need to sort out
the "blocks"...
> I've had another look and noticed that the syntax says that each
> Resent- block must be separated by at least one Received: line.
> Section 3.6 again:
>
> fields = *(trace
> *(resent-date /
> resent-from /
> ...))
> *(orig-date /
> from /
> ...)
I hadn't appreciated that either. Well spotted!
> When Exim is assisting the MUA perhaps it should expect any Resent- lines
> to appear at the start of the header before the first Received: line
> (later Resent- lines being from previous resendings).
Yes, excellent. That is a nice clear specification which is
straightforward to explain and to implement. Thank you for doing the
research.
However, this is all too late now for 4.20, which I am currently trying
to "put to bed".
> Digression: The anti-spam research group has been arguing a lot about
> improving the traceability of email. One of their suggestions is to
> add an RR type to the DNS similar to MX records but for email emitters
> rather than receivers. Email from a machine that isn't listed as one of
> the return path's domain's email emitters is therefore obviously forged.
So I'm out in Uganda, as I will be next month, and the network is flaky,
and I can't manage to reach my home server in order to send out mail
from my laptop - I therefore try sending it straight out from the
laptop, which is on some DHCP dynamic address... Sigh.
> However this idea interacts badly with .forward files since they send
> email on without changing the return path. The general opinion seems to
> be that the mailing list BCP of changing the return path when forwarding
> the email should be applied to all forwardings. However this changes
> the way you must deal with bounces that result from .forwardings...
Absolutely! As far as I can see, if the forwarding is unconditional, you
are chopping off the possibility of doing anything useful with bounces
if you change the return path.
> Anyway, my point is that perhaps Exim might optionally do the Resent-
> thing for redirects when changing the return path.
Not sure about that. Who is doing the redirection? And in a mailing
list, the last thing you want is to insert Resent-To: lines.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
