[Dovecot] Problems with the IMAP proxy after upgrading from dovecot 1.1.16 to 1.211

[Holger Richter]

>> >> May  7 14:47:42 ttt dovecot: auth(default):
>> >> worker-server(uid,yyy.yyy.yyy.yyy): Aborted: Lookup timed out
>> >> May  7 14:47:42 ttt dovecot: auth-worker(default): mysql: Connected to
>> >> lll.lll.lll.lll (imapauth)
>> >
>> > "Lookup timed out" really shouldn't be happening.. That sounds like
>> > Dovecot's MySQL connections hangs after a while? You have some stateful
>> > firewall between Dovecot and MySQL that drops idling connections and
>> > afterwards starts dropping the connection's packets?
>>
>> Indeed, there is a firewall with stateful inspection between Dovecot
>> and MySQL.
>
> Right, so the "Lookup timed out" works as intended. But I guess it
> should automatically retry when that happens. There would still be that
> 1 minute delay before that happens though.
>
>>  The only workaround is a downgrade to Dovecot 1.1.20.
>
> Wonder what v1.1 does differently. I can't think of anything, really.
> The main fundamental problem is still that mysql connection hangs and
> the hang can't be detected/avoided. I think the right fix here would be
> to change your firewall settings..
>
>> I think my problem has to do with the changes in
>> src/auth/auth-worker-server.c in changeset 8859.
>
> 8559:b0bc4519332f?

Yep.