On Tue, Mar 09, 2004 at 11:14:39AM -0500, Nick Fisher wrote:

> > In the headers of your message:
> >   From [EMAIL PROTECTED]
> >   Received: from mail.apache.org (daedalus.apache.org [208.185.179.12])
> >
[snip]
> >
> The problem with that is that it takes no account of forwarding.
> 
> Domain A, B and C.
> 
> If I send a mail from domain A to domain B, that is then forwarded to domain
> C it will appear to be spoofed as domain B is not in domain A's SPF records.

It does not *appear* to be spoofed, it *is* spoofed.  Yes, SPF stops that.

You were already pointed at the difference between "From " (note the space)
and "From:".  As you can see, SPF works perfectly for the spamassassin
mailing list.

Now consider a "mailing list" with just one subscriber.

domain A:  home of the author of a message
domain B:  hosting said "list"
domain C:  home of the sole subscriber to that list

[EMAIL PROTECTED] sends a message to [EMAIL PROTECTED]  [EMAIL PROTECTED] setup
forwarding.  All domainB has to do when it transfers the message to
domainC is:

1: make sure the envelope sender address is at domainB, not domainA
2: there is no #2.

No SRS is needed.  No other special tricks are needed.  SPF does not
break forwarding.  SPF breaks spoofing; and does not care if spoofing
is done by someone with good intentions or someone with bad intentions.

SRS is just a smart way _for_domainB_ to generate a *local* address that
has the address of [EMAIL PROTECTED] encoded in it.  DomainB could keep a
database instead.

But what about bounces?  Well, if [EMAIL PROTECTED] screws up, [EMAIL PROTECTED]
will have to educate userB.  If domainC screws up, that's between domains
B and C.  DomainA succesfully delivered the message to its destination.

cheers,
Alex
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