On Tuesday 21 October 2003 20:04, Izzy Kindred wrote:
The message now arrives at b.com, and is forwarded as follows:
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Return-Path: b(_at_)b(_dot_)com (or should this be
bounce-manager(_at_)b(_dot_)com?)
From: a(_at_)a(_dot_)com
To: c(_at_)c(_dot_)com
Spf-Forward: <forward-count> b(_at_)b(_dot_)com c(_at_)c(_dot_)com <hmac-sha1
hash>
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This may work, but I am not sure it is the right way of doing things.
I suspect that final RFC ratification will be influenced mainly by ISP/Network
type people, rather than end users. And there are two very different
requirements from each camp.
The above addition of headers may give a traceability, and lots of other bells
& whistles, but the admin of an MTA is opnly interested in 1 thing -
delivering legitimate email. Spam, worms/viri etc from forged and
non-existant addresses should be IMMEDIATELY rejected, not bounced, by
issuing a 5xx response at the DATA command. A forged email is simply not
allowed onto my server. Spam is not only getting more numerous, it is also
getting more bulky. Once it is on any system, it is too late - and to have to
wait until the whole message is received, simply to validate the header, is
wasteful - especially as the mail will probably be resent at a later date.
Which leaves the rewriting of the envelope sender as the most effective way of
dealing with the problem. mail can be rejected before it has been submitted.
Even though persuading forwarders to rewrite the envelope-sender may be a
problem, I think eventually most MTA admins will 'come round' to the idea
_IF_ they can see the bandwidth reduction as a real benefit. Coupling this
with a modification of existing RFC to allow HELO verification & rejection
provides a simplicity and effective solution to our problems.
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