steve:
>
>
> Hi,
>
> Thankyou for taking the time to reply.
>
> All maps on my setup are MySQL backed. I have no local mail as such. All
> domains are virtual (I think that's the correct postfix terminology?)
>
> # postconf | grep mysql
>
[lotsa maps]
> > That depends on the purpose of the table lookup. For example, if
> > the error could result in a delivery error, then the error is
> > critical and Postfix defers delivery.
>
> That makes sense. The problem is in my case it did't result in a
> delivery error, it resulted in a taking of delivery error. The
> servers failed to receive any email for a couple of hours as a
> result of the MySQL outage. Here's an example of the kind of
> messages I have on my logs...
You mean, Postfix deferred the mail transaction, instead of making
the wrong decision what mail to reject or accept, and instead of
making the wrong decision where to deliver mail.
> 2014-10-18T00:02:43.000+01:00 maroon postfix/smtpd[75860]: warning:
> proxy:mysql:/usr/local/etc/postfix/mysql/mynetworks.cf: table lookup problem
[lots more table lookup errors]
> 2014-10-18T00:05:16.000+01:00 maroon postfix/smtpd[75860]: lost connection
> after EHLO from unknown[213.199.154.78]
>
> A 'table lookup problem' resulting is not being able to take receipt
> of email is a critical situation in my setup.
Yes. Postfix defers delivery when database lookup fails that could
result in accepting or rejecting the wrong mail or delivering mail
to the wrong place.
It is your responsibility to take action when Postfix logs database
lookup errors. I suggest that you run a logfile watcher that raises
an alarm.
Wietse
