[GTALUG] Sendmail Changes

[Giles Orr]

On Tue, 29 Jan 2019 at 21:06, Chris Tyler via talk <talk at gtalug.org> wrote:

> I have a very old sendmail configuration on a VM on a dying server. I need
> to move it to a stable hw platform, so I took the sendmail setup and
> migrated it to a new system with a current Sendmail installation.
>
> The previous Sendmail configuration worked fine and was trusted by remote
> senders. It did not have SPF, DKIM, or DMARC set up. The new Sendmail
> server worked fine (worked as expected), but was not trusted by some remote
> MTAs sending TO it - including those used by Google/gmail. This seems odd
> because the only real difference between the two configurations is the
> Sendmail version -- something seems to have changed in the software. I
> reverted to the original system after these experiments last summer, but
> haven't circled back to it until now, when the failure of the underlying hw
> is forcing my hand.
>
> I haven't been following the evolution of Sendmail. I need to set up a
> better long-term solution (possibly with another MTA, and definitely with
> SPF+DKIM+DMARC), but in the short term I urgently need to migrate this
> configuration over to a box that isn't failing. Is anyone aware of Sendmail
> changes (either in behavior or defaults) that would explain how remote
> servers regard the MX?
>

Disclaimer: I know nothing about sendmail.

However, it occurs to me that I wouldn't put it past Google to check your
sendmail version, and let you get away with not having SPF+DKIM+DMARC on
the really old version but block you on newer versions that don't have
them.  Seems to me they maybe shouldn't accept the older version at all for
security reasons, but clearly they do ...

-- 
Giles
https://www.gilesorr.com/
gilesorr at gmail.com
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