Re: (DMARC) Why mailing lists are only sort of special

[Yoav Nir <[e-mail]>]

On Apr 17, 2014, at 4:11 PM, Martin Rex <[e-mail]> wrote:

> Yoav Nir wrote:
>> 
>> On Apr 17, 2014, at 9:35 AM, Dave Cridland <[e-mail]> wrote:
>>> 
>>> Right now, my MUA treats this as a message
>>> "From John R Levine <[e-mail]>". This means that any policy
>>> on the message origination comes from looking solely at the taugh.com
>>> domain. We'll pretend it has a DMARC policy. Herein lies the
>>> Yahoo/DMARC issue, because unless your policy essentially stipulates
>>> that the IETF is allowed to spoof you, we're stuck.
>> 
>> Then perhaps this is what needs to change. John R Levine did not send
>> you a message. He sent a message to the list. It is the list software
>> that sent you a message. So perhaps the From field should have been
>> ?From: IETF Mailing list on behalf of John R Levine <[e-mail]>?.
> 
> But that is EXACTLY what the IETF mailing list exploder *IS* doing
> exactly as it has been specified for ages:
> 
> https://tools.ietf.org/html/rfc822#section-4.4.2
> https://tools.ietf.org/html/rfc822#appendix-A.2
> 
> https://tools.ietf.org/html/rfc5322#section-3.6.2
> 
>            The "From:" field specifies the author(s) of the message,
>   that is, the mailbox(es) of the person(s) or system(s) responsible
>   for the writing of the message.  The "Sender:" field specifies the
>   mailbox of the agent responsible for the actual transmission of the
>   message. 
> 
>  From: Yoav Nir <[e-mail]>
>  Subject: Re: (DMARC) Why mailing lists are only sort of special
>  Errors-To: [e-mail]
>  Sender: ietf <[e-mail]>
>  Date: Thu, 17 Apr 2014 13:50:30 +0300
>  Message-ID: <[e-mail]>
>  To: Dave Cridland <[e-mail]>
>  CC: "[e-mail]" <[e-mail]>
> 
> 
> Something as old as Outlook 2003 will properly display a message
> that is received with a "Sender:" as "<Sender> on behalf of <From>”

A client as new as Mail.app on Mac OS X 10.9 does not. 

Obviously the Sender: field is not where the DMARC implementations use for checking policy.

Yoav