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Re: [dmarc-ietf] Using CNAME records to DMARC templates causes issues

John Levine <johnl@taugh.com> Wed, 03 March 2021 18:15 UTC

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Date: Wed, 03 Mar 2021 13:15:04 -0500
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From: John Levine <johnl@taugh.com>
To: dmarc@ietf.org
Cc: tjw.ietf@gmail.com
In-Reply-To: <CADyWQ+HY_3qT6zb1Gr4tQYVZcpDSQ=xCE4b1J33BLeLdTNvzdw@mail.gmail.com>
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Subject: Re: [dmarc-ietf] Using CNAME records to DMARC templates causes issues
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In article <CADyWQ+HY_3qT6zb1Gr4tQYVZcpDSQ=xCE4b1J33BLeLdTNvzdw@mail.gmail.com> you write:

>As for those few folks who have seen DNS issues around using CNAMEs, I really want to
>hear from you off list.  Tracking down esoteric DNS error operational behavior is
>something I am slightly obsessive about.   "I'm from the DNS, and I'm here to help"

Yup.  I am thinking back to the 1990s when qmail put in a hack that used ANY queries
to cirumvent a CNAME big in some version of bind, and it took us a decade to get rid
of it.

CNAMEs work fine, and if they appear not to, your DNS library is 99.9% likely to be the problem.

-- 
Regards,
John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly

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