spf-discuss
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Re: [spf-discuss] Re: Forwarder whitelisting reloaded

2008-01-16 14:52:56
At 12:12 AM 1/16/2008 +0100, Alessandro Vesely wrote:
David MacQuigg wrote:
Alessandro Vesely wrote:
I'm not sure aol.com should be labeled "MDA".
That is their role in this exchange.  Of course, as a company
they provide a lot of other services, including Sender,
Transmitter, Receiver, Forwarder, Webhost, Domain Registrar,
Targeted Advertising ...

In addition, there is a second border after the
Forwarder(s). The latter is what makes it difficult for the
receiver to reuse spam knowledge gathered by the recipient.
??? There is a *direct* relationship between the Receiver and
the Recipient.  The Recipient should send spam reports
directly to the Receiver, not AOL, not SpamCop, not anyone
who has no *first-hand knowledge* of the source of the spam.

This is where I get lost. We don't actually mount AOL's hard disks on the 
Receiver host --which I'd call "direct". Formally, we engage an SMTP (or LMTP) 
transaction with their server, playing the transmitter's role.

Maybe we could show direct relationships with == and indirect relationships 
with ~~ and "same ADMD" relationships as MTA1/MTA2.  The situation we are 
discussing is then illustrated as:
                                                      
                               /                /====================\
Sender(s) ==> Transmitter --> / --> Receiver/Forwarder ~~> MDA ==> Recipient
                             /
                          Border       (box67.com)      (aol.com)  

What I mean by a "direct relationship" is a contract, or at least a signup on a 
website.  As an example, my service box67.com acts as a Receiver and Forwarder 
for an individual, Robert, who has asked us to forward his mail to aol.com.  
Robert has an account at aol.com, so there is also a direct relationship 
between him and AOL.  Those two direct relationships establish an indirect 
relationship between box67.com and aol.com, at least for this one Recipient.

As a consequence of this indirect relationship with AOL, in principle, 
box67.com can say to AOL, "Hey, we are buddies, turn OFF your spam filter, and 
don't complain about what we send to Robert."  AOL may be surprised by that 
assertion, but after checking with Robert, they should say, "You are right, 
Robert wants you to forward everything to his mailbox."

The relationship among the Agents in an MRN is very different than between 
totally unrelated parties on the open Internet.  Robert is in charge of this 
particular MRN, as he is the one who made all the arrangements.  As you have 
noticed, the MRN can change with every message, even to the same Recipient.  I 
have multiple accounts at yahoo.com, and each one has a different set of 
forwarding arrangements.

-- Dave

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