Re: [Asrg] Re: Disaster looming: SPF

[Devdas Bhagat <devdas at dvb.homelinux.org>]

On 09/12/04 23:42 +0100, Frank Ellermann wrote:
> Devdas Bhagat wrote:
> 
> > What about using multiple .forwards or equivalent?
> 
> Forwarding is something the receiver does.  Sender policies are
> something the senders publish.  Senders don't know and don't
> care what a receiver does, it's his problem.  Senders only say:
> 

Right. But .forward is still used and SPF breaks that. SRS is a hack to
try and prevent it breaking.

> "These are the IPs you as 3rd party see in MAIL FROM me to you
>  at your MX, any other mail claiming to be MAIL FROM me at your
>  MX is forged, don't bother to accept it, please reject it."
> 
> Why's that so difficult to understand ?  Senders have no idea
> how a receiver forwards mail behind his MX, it's none of their
> business.  The receiver is free to do whatever he likes.  And
> if his mail setup is broken he owns the pieces.

Breaking a known working feature is not a good way to keep those
power users happy.

> > Or people using the bounce feature in mutt?
> 
> Is that the stuff where I get mail claiming to be MAIL FROM me,
> but in fact it's from somebody else ?  I'd report it to abuse@
> for the corresponding IP, it's forged.  But actually it should
> never arrive if publishers of -all policies also check SPF on
> their own MX.

No. Mutt adds a Resent-from header and keeps the original mail
information. This needs deliberate action by the sender, and is the
equivalent of a .forward (slightly loosely speaking) for that mail.

Devdas Bhagat

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