He is correct, MX records must not point to CNAMEs. See section 10.3 RFC
2181 for details.
On Sat, Aug 13, 2016 at 6:49 AM, Arnt Gulbrandsen
<arnt(_at_)gulbrandsen(_dot_)priv(_dot_)no>
wrote:
Hi,
I’ve just run across a biggish sender that insists that MX records point
to A/AAAA records and therefore cannot send mail to a site whose MX points
to a CNAME (which in turn points to an A).
The sending site’s FAQ says this is due to applicable FAQs, without citing
chapter and verse. Ahem. I found a question on serverfault which claims
1123 forbids pointing to CNAME in MX, but don’t see any applicable text in
1123. I do see something in 974... but I’d like to hear your opinion on the
issue.
Arnt
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*GEORGE SCHLOSSNAGLE*
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