"Chris" == Chris Haynes <chris(_at_)harvington(_dot_)org(_dot_)uk> writes:
Chris> That virus-carrying message will now be sent, unauthorised
Chris> and unchecked by Sender-ID, to whatever innocent victim was
Chris> chosen by the forger.
Chris> This is the 'harm' that Sender-ID would be causing. If
Chris> Sender-ID had not been used, this second, virus-carrying
Chris> message would not have been created and sent.
Backscatter (ie bounce messages sent to forged addresses) is already a
_huge_ problem for many people, and will need to be solved whatever
happens in the MARID front.
People are working on it (schemes that modify the MAIL FROM such as
BATV or SES, schemes that keep track of Message-IDs, schemes that add
additional tracking headers).
Your argument basically boils down to saying I should never reject any
SMTP transaction because it might result in backscatter. I don't buy
it. Backscatter is a problem; let's fix it (but not here).
-roy