Re: Microsoft O365 labels nanog potential fraud?

[DaKnOb <daknob.mac () gmail com>]

Indeed, in more detail (which I omitted for simplicity), these checks are performed in a series of headers, the last of 
which is the From: header. I think the “envelope-from” is either the first or the second in this 5-point list.
That said, there are a lot of implementations out there that do not respect that and treat the From address as the 
sender whose honesty must be verified. Every time I send mail to a mailing list from my own domain, due to DMARC I get 
back several reports of SPF and DKIM fail, mainly because the mailing list messed up something. 

> On 29 Mar 2017, at 18:32, William Herrin <bill () herrin us> wrote:
>
> On Wed, Mar 29, 2017 at 11:25 AM, Grant Taylor via NANOG <nanog () nanog org>
> wrote:
>
> > Every SPF implementation I've seen has checked the SMTP envelope FROM
> > address /and/ the RFC 822 From: header address.
>
> Hi Grant,
>
> The gold standard, Spamassassin, does not. Indeed, the message to which I
> reply was scored by spam assassin as "SPF_PASS" even though you do not
> include NANOG's servers in the SPF record for tnetconsulting.net.
>
> Regards,
> Bill Herrin
>
>
> -- 
> William Herrin ................ herrin () dirtside com  bill () herrin us
> Dirtside Systems ......... Web: <http://www.dirtside.com/>