Wow! Thanks for the Holmesian sleuthing Brandon! I will take this info and 
Ken's good advice to let the gmail user know about their bi-directional 
forwarding's potential for problems.

Thanks,
-Terry

> On Nov 15, 2016, at 1:46 PM, Brandon Long <[email protected]> wrote:
> 
> So, I looked up the actual message.  It is being forwarded to a hotmail.com 
> account normally, and then forwarded back.
> 
> It looks like Hotmail/Outlook is rewriting the envelope sender back to your 
> account.
> 
> Ie, it's [email protected] -> [email protected]
> [email protected] -> [email protected]
> [email protected] -> [email protected] -> this fails because of DMARC policy failure.
> 
> and then you get the bounce.
> 
> Our rewriting there is pretty easy to understand, pretty normal application 
> of a VERP, but it seems likely they are undoing the rewrite on purpose.  If I 
> had to guess, they are doing the rewriting to make other things work better, 
> and it's effect on the forwarding case isn't the primary reason.
> 
> As for why a user would do this, if they're using both accounts regularly, 
> the easiest is to set up forwarding in both directions and hope that message 
> deduplication takes care of stopping any loops.
> 
> Brandon
> 
> On Tue, Nov 15, 2016 at 1:22 PM, Michael Wise via mailop <[email protected]> 
> wrote:
> 
> I can understand the desire to do it, but ... in a forum such as this, yer 
> gonna have to get around to giving us the real data sooner or later, so I'd 
> suggest providing it at the outset, just because.
> 
> Aloha,
> Michael.
> --
> Michael J Wise
> Microsoft Corporation| Spam Analysis
> "Your Spam Specimen Has Been Processed."
> Got the Junk Mail Reporting Tool ?
> 
> -----Original Message-----
> From: Terry Barnum [mailto:[email protected]]
> Sent: Tuesday, November 15, 2016 12:59 PM
> To: Michael Wise <[email protected]>
> Cc: David Sgro, Dataspindle <[email protected]>; [email protected]
> Subject: Re: [mailop] Confused by bounce
> 
> Thanks Michael. Just my habit of obfuscating domains with example.com. 
> Probably counter-productive here.
> 
> -Terry
> 
> > On Nov 15, 2016, at 11:52 AM, Michael Wise <[email protected]> 
> > wrote:
> >
> >
> > Dunno whether this is serious or not, what with the reference to 
> > example.com and all, but if it is ...
> > I draw your attention to the SPF record’s single clause.
> > If this was a test, it was poorly chosen.
> >
> > $ host -t txt example.com
> > example.com descriptive text "v=spf1 -all"
> >
> > Aloha,
> > Michael.
> > --
> > Michael J Wise
> > Microsoft Corporation| Spam Analysis
> > "Your Spam Specimen Has Been Processed."
> > Got the Junk Mail Reporting Tool ?
> > -----Original Message-----
> > From: mailop [mailto:[email protected]] On Behalf Of David Sgro, 
> > Dataspindle
> > Sent: Tuesday, November 15, 2016 11:26 AM
> > To: Terry Barnum <[email protected]>; [email protected]
> > Subject: Re: [mailop] Confused by bounce
> >
> > Possibly a manual blacklist by that domain?
> >
> > -----Original Message-----
> > From: mailop [mailto:[email protected]] On Behalf Of Terry Barnum
> > Sent: Tuesday, November 15, 2016 2:02 PM
> > To: [email protected]
> > Subject: [mailop] Confused by bounce
> >
> > If we send email to a specific gmail user we receive a bounce from Hotmail 
> > saying it can't deliver due to our DMARC policy. Postfix logs show the 
> > email being delivered and accepted by gmail. Email to other gmail users 
> > goes through fine.
> >
> > Postfix delivery-
> > Nov 14 18:12:00 mail.example.com postfix/smtp[7000]: 3tHrVm0qyVzKk7bl: 
> > to=<[email protected]>, relay=gmail-smtp-in.l.google.com[173.194.203.26]:25, 
> > delay=0.76, delays=0.02/0.01/0.48/0.24, dsn=2.0.0, status=sent (250 2.0.0 
> > OK 1479175920 p62si24555443pfi.27 - gsmtp)
> >
> > Bounce-
> > Reporting-MTA: dns;BLU004-OMC4S37.hotmail.com
> > Received-From-MTA: dns;NAM04-SN1-obe.outbound.protection.outlook.com
> > Arrival-Date: Mon, 14 Nov 2016 18:12:05 -0800
> >
> > Final-Recipient: rfc822;[email protected]
> > Action: failed
> > Status: 5.5.0
> > Diagnostic-Code: smtp;550-5.7.1 Unauthenticated email from example.com is 
> > not accepted due to domain's
> > 550-5.7.1 DMARC policy. Please contact the administrator of example.com 
> > domain if
> > 550-5.7.1 this was a legitimate mail. Please visit
> > 550-5.7.1  
> > https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsupport.google.com%2Fmail%2Fanswer%2F2451690&data=02%7C01%7Cmichael.wise%40microsoft.com%7Ce518fcb88cc74cb11d2b08d40d8e5c00%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636148352462936043&sdata=Tp0ESIrlQCEezqrPx6Dea3leznKOTfJZTh07%2B0iGTyw%3D&reserved=0
> >  to learn about the
> > 550 5.7.1 DMARC initiative. xz8si20469041pab.182 - gsmtp
> >
> > I'm confused as to how this can happen. Could the gmail user be forwarding 
> > received email to a hotmail account and then back to gmail, breaking DMARC?
> >
> > Thanks,
> > -Terry
> >
> > Terry Barnum
> > digital OutPost
> > Carlsbad, CA
> >
> > https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.dop.com&data=02%7C01%7Cmichael.wise%40microsoft.com%7Ce518fcb88cc74cb11d2b08d40d8e5c00%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636148352462946051&sdata=HvEiLW3Jx%2BtN3hX0fdktiltl2EISl8hYt1xzuJsBuNI%3D&reserved=0
> > 800/464-6434
> >
> >
> >
> > _______________________________________________
> > mailop mailing list
> > [email protected]
> > https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fchilli.nosignal.org%2Fcgi-bin%2Fmailman%2Flistinfo%2Fmailop&data=02%7C01%7Cmichael.wise%40microsoft.com%7Ce518fcb88cc74cb11d2b08d40d8e5c00%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636148352462946051&sdata=qaFPrY5RMNhkSdIMg1eiknu%2BH1HLB0o7qLyr%2FTyJmH8%3D&reserved=0
> > _______________________________________________
> > mailop mailing list
> > [email protected]
> > https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fchilli.nosignal.org%2Fcgi-bin%2Fmailman%2Flistinfo%2Fmailop&data=02%7C01%7Cmichael.wise%40microsoft.com%7Ce518fcb88cc74cb11d2b08d40d8e5c00%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636148352462946051&sdata=qaFPrY5RMNhkSdIMg1eiknu%2BH1HLB0o7qLyr%2FTyJmH8%3D&reserved=0
> 
> Terry Barnum
> digital OutPost
> Carlsbad, CA
> 
> https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.dop.com&data=02%7C01%7CMichael.Wise%40microsoft.com%7C35e9509ba5a847062f8608d40d9a4412%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636148403596535028&sdata=zcIQtMW%2FDE%2BVRbXfKgbZLcLTOwOE0KRuo%2FnMsEeQHLo%3D&reserved=0
> 800/464-6434
> 
> 
> _______________________________________________
> mailop mailing list
> [email protected]
> https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop
> 

Terry Barnum
digital OutPost
Carlsbad, CA

http://www.dop.com
800/464-6434



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