On Wed, Sep 27, 2017 at 07:00:39PM -0700, Michael Fox wrote:
> > This is an obsolete option in Sendmail that violates decades old SMTP
> > standards, CNAME canonicalization of recipient domains went away in
> > RFC 2821 and there are many email domains that are aliases where the
> > mailbox address is expected to remain unmangled by CNAME expansion of
> > the domain part. The operators of the sending system are stuck in the
> > distant past.
>
> Thanks Viktor. Yes, I see section 3.6 now explicitly allows "CNAME RRs
> whose targets can be resolved, in turn, to MX or A RRs", which was the case
> in my situation.
>
> Good to know that Postfix does it better!
Even Sendmail does it better in default and recommended configurations,
the users in question are deliberately choosing to continue no longer
sound practices.
--
Viktor.
