[Dovecot] status=undeliverable (lost connection with mail.larptreff.de[private/dovecot-lmtp] while sending MAIL FROM)

[Michael Grimm]

On 2013-11-07 8:53, Jan Phillip Greimann wrote:

This is dovecot 2.2.7, postfix 2.10.2, all addresses type virtual 
mailbox domain class, and dovecot/lmtp delivery.

> I noticed a strange log-entry since the last day:
> 
> Nov  7 08:34:42 hetzner postfix/lmtp[3764]: 61CB01A3938:
> to=<jg+introversion at larptreff.de>,
> relay=mail.larptreff.de[private/dovecot-lmtp], delay=0.05,
> delays=0.01/0.01/0.02/0.01, dsn=4.4.2, status=undeliverable (lost
> connection with mail.larptreff.de[private/dovecot-lmtp] while sending
> MAIL FROM)

I noticed as well, that some of my addresses lead to unusual rejections 
never anticipated before:

postfix/lmtp[1234]: 3dFbVw2NVmz6SL: to=<example at example.com>, 
relay=mx1.example.com[private/dovecot-lmtp], delay=0.04, 
delays=0.03/0/0/0.01, dsn=4.4.2, status=undeliverable (lost connection 
with mx1.example.com[private/dovecot-lmtp] while sending MAIL FROM)

> It seems this only happens on mails with "+"-Delimiter.

In my case regular addresses are rejected as well (see example).

What I really do not understand is that out of e.g. 50 different 
recipient addresses of one virtual mailbox domain only a few are 
rejected, the other pass as usual. This is not random, some addresses 
pass always, others fail reproducible.

> In my opinion there is only one thing which could cause this problem:
> I updated my dovecot on 2013/11/04 from 2.2.6-1~auto+36 to 
> 2.2.7-1~auto+2

I updated two days ago.

> I will try to downgrade again, did someone have a clue?

I have no clue what leads to those random rejections of recipient 
addresses. After setting ...

| warn_if_reject reject_unverified_recipient

... those mails are accepted. But I do consider this a temporary 
workaround.

Regards,
Michael