Yahoo DMARC breakage

Jeff Kell jeff-kell at
Thu Apr 10 00:02:16 UTC 2014

On 4/9/2014 7:22 PM, Larry Sheldon wrote:
> On 4/9/2014 5:11 PM, bmanning at wrote:
>> On Wed, Apr 09, 2014 at 05:49:27PM -0400, Jeff Kell wrote:
>>> The most "sane" out-of-mind response should only be sent *if* the
>>> out-of-mind person is named explicitly as a recipient in the RFC822
>>> header.  Anything To: somelist at somehost does not qualify :)
>>> Jeff
>>     and just how is an algorithm supposed to detect that
>>     <jeff-kell at> is a single human and not a list?
> It is really too bad that there is not place to put a "precedence"
> that the software could key on--with values like "bulk" or "junk" or
> "list".

Headers of your message include:

> Precedence: list
> List-Id: North American Network Operators Group <>
> List-Unsubscribe: <>,
>  <mailto:nanog-request at>
> List-Archive: <>
> List-Post: <mailto:nanog at>
> List-Help: <mailto:nanog-request at>
> List-Subscribe: <>,
>  <mailto:nanog-request at>
> Errors-To: at
> Return-Path: at

Proper mail clients can provide "list links" based on the List- headers,
but few if any actually do.

So take your pick, but my point remains, it still retains:

> Date: Wed, 9 Apr 2014 18:22:51 -0500
> From: Larry Sheldon <LarrySheldon at>
> Organization: Maybe tomorrow
> User-Agent: Mozilla/5.0 (Windows NT 5.1;
>  rv:24.0) Gecko/20100101 Thunderbird/24.4.0
> To: <nanog at>
> Subject: Re: Yahoo DMARC breakage

And I'm nowhere mentioned.  I only appear in the "envelope RCPT TO:<>
RFC821 header", nowhere in the RFC822 header.

It's not rocket science if you have headers available (which even
Outlook can see, although you have to jump through a few hoops to see them).


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