lists and DMARC and ARC, was Incoming SMTP in the year 2017 and absence of DKIM
mike at mtcc.com
Wed Nov 29 23:03:17 CST 2017
On 11/29/2017 03:00 PM, Grant Taylor via NANOG wrote:
> On 11/29/2017 03:46 PM, Michael Thomas wrote:
>> You know what the original header was via the signature. You can take
>> the delta of the current subject line and remove any additions and
>> validate the signature. Whether you're happy with the additions is a
>> different concern,
> Are you referring to the optional z DKIM-Signature tag?
> Or are you referring to brute forcing what the subject was in order to
> derive the delta of the current subject? This would be compounded by
> any number of other changes to (over)singed headers / body portion.
>> If I were constructing a spam filter out of it, I'd give a lot of
>> prejudice to anything added, but that's outside of
>> what you can do within the bounds of the spec.
> *If* the z tag was included in the DKIM-Signature header, I can see
> how this would work and I agree with your distrust of said additions /
Yes, with the z=
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