[Mailman-Users] Emails from yahoo members, are getting rejected by yahoo, "Service Unavailable".
Stephen J. Turnbull
stephen at xemacs.org
Fri Apr 18 16:30:49 CEST 2014
Sylvain Viart writes:
> Le 18/04/2014 09:41, Alain Williams a écrit :
> >> I may have missed some topic, but why SRS
> >> (http://en.wikipedia.org/wiki/Sender_Rewriting_Scheme) doesn't
> >> come to rescue here?
> > SRS rewrites the *envelope* sender.
> > My understanding is that the YAHOO DKIM uses the From: header,
> > not the envelope sender.
> Oh I see. Thanks.
> So to use mail's Header terminology, only the Return-path: is modified,
> not the From:
No, the envelope sender often does end up in Return-Path, but it need
not. The envelope sender is the entity in the SMTP "MAIL FROM"
command, not anything in the headers.
> Is this related to DMARC in general?
Yes. DMARC is designed to work with "From alignment", that is,
authenticating the domain in the from header. It *can* also
authenticate the mailbox using DKIM, but there's no guarantee that a
third party can see.
The reason for this is that the DMARC authors are concerned about
phishing, which basically works by sending a fake "From". Therefore
they want to ensure that only the real domain can send "From" that
> May be not corrected by SRS, because of DMARC is more recent than
They're completely unrelated.
> Or this is a yahoo challenging with a somewhat too strong
Yahoo is following the DMARC standard. They don't believe it is "too
strong". See above.
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