Dovecot/MSQL issue

lorek dundir at
Wed Jul 3 03:19:36 EEST 2019


I was having an issue with the tcp socket @ I'd tried various
different modifications based on the logs and the issue had remained
I had built up the environment in a dockerfile and worked on it through the
weekend so the problem was replicable across instances up until this

I ended up switching over to using the socket yesterday and only checked
out to the previous commit this morning to run a few additional tests on
the problematic part. For whatever reason, the issue is now completely gone.

At this point, I'm thinking this must be a docker issue.

The only notable (minor) differences between this past weekend and today
are an AER/ASPM kernel error that was logging on the host.
The paste is here:

The main difference between the weekend and today is the additional line
included saying it can't find device of ID 0008. That wasn't showing up
over the weekend.
I think given this experience I may have to revisit my testing methodology
when working with docker.

Best Regards,

On Tue, Jul 2, 2019 at 12:38 PM John Fawcett via dovecot <
dovecot at> wrote:

> On 01/07/2019 09:48, lorek via dovecot wrote:
> > Actually, it seems I may have been wrong in initial assumption that
> > the issue with the client was that it was being identified to mysql as
> > coming from localhost when connecting via tcp.
> > This is what syslog indicated as a reason for the failure but its not
> > the whole picture.
> >
> > As John mentioned I am trying to have dovecot connect over TCP to
> > mysql (not using the socket), and the issue looked like the cause was
> > the identified by portion of mysql being read by either mysql
> > incorrectly or the domain portion being overwritten on dovecot's end
> > (I don't know about the internals enough to say for sure where).
> >
> > Just as due dilligence, I added credentials for a mysql user
> > identified by localhost and removed the jail since the dovecot error
> > was stating that it failed for connection by user@'localhost' (where
> > there weren't credentials).
> > After adding the credentials, I performed all the usual mysql tests
> > before moving testing up to dovecot and still get an auth failure. The
> > log seems to be a bit of a red herring or at the minimum doesn't show
> > the whole picture.
> >
> > Replacing the connection string host with the socket (host=localhost)
> > and everything works, and using an external IP that's not
> > works as expected as well. (confirmed by standing up two isolated
> > mysql and dovecot containers and setting auth up over the bridge).
> >
> > If the issue was caused by user@'localhost' creating the credentials
> > should have resolved it, and it didn't. So something weird is going on.
> > I've got the environment built up in a dockerfile I can provide if
> > anyone wants to dig into what's causing it.
> >
> > In the meantime due to time constraints, I'll just be working with the
> > socket file from now for hosts running most of the mail stack all in one.
> >
> > Best Regards,
> > Lorek.
> Lorek
> If you have user at localhost as a user in mysql you will be able to
> connect with either of these options:
> - a tcp socket via an ip address that resolves to localhost
> - a unix socket via hostname localhost.
> If you have user at as a user in mysql you will be able to
> connect only via:
> - a tcp socket using ip address
> John
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