[Asrg] processing mailing list headers (was FeedBack loops)

[Steve Atkins]

On Nov 13, 2008, at 10:09 PM, Matthias Leisi wrote:

>
> Franck Martin schrieb:
>
>> So there is a need for a process at the MUA and MTA to make sure the
>> unsubscribe header is valid and will be honored.
>
> Which would be roughly equal to "make sure the Received: headers and  
> the
> From: header are valid"?
>
> "valid" would mean 1) it is technically resolveable (as an email
> address, an URL, whatever) and 2) it points to a non-spammer that will
> not use the information received as eg a confirmation of an email
> address read by an end-user.
>
> I have my doubts that this approach will succeed. For such an approach
> to succeed, it would need to be mutually secured/authenticated, but I
> don't see a feasible method for this at the moment.

A list of trusted ESPs, probably provided by a certification authority  
is
one approach. Authenticated by peer IP address or dkim signature.

> (Of course, it would be technically possible, but organisationally
> expensive and may have undesireable side-effects.)

Hotmail do it, and it works fine for them. I'm fairly sure some of the
other big names do it too.

Cheers,
   Steve