[Dovecot] LMTP : Can't handle mixed proxy/non-proxy destinations

[Alexis Lelion]

Hello,

In my current setup, I uses two mailservers to handle the users
connections, and my emails are stored on a distant server using NFS
(maildir architecture)
Dovecot is both my IMAP server and the delivery agent (LMTP via postfix)
To avoid indexing issues related to NFS, proxying is enabled both on IMAP
and LMTP. But when a mail is sent to users that are shared between the
servers, I got the subject mentionned error in the logs :

Jan 25 09:05:12 mail01 postfix/lmtp[23934]: A92709300DB: to=<
user_on_mail02 at domain.com>, relay=mail01.domain.com[private/dovecot-lmtp],
delay=0.07, delays=0.01/0/0/0.06, dsn=4.3.0, status=deferred (host
mail01.domain.com[private/dovecot-lmtp] said: 451 4.3.0 <
user_on_mail02 at domain.com> Can't handle mixed proxy/non-proxy destinations
(in reply to RCPT TO command))

>From what I saw, the mail is then put in the queue, and wait until the
next time Postifx will browse the queue. The mail will then be correctly
delivered on "mail02". However, the "queue_run_delay" postfix parameter
is set to 900, which means that the mail will be delivered with a lag of
15 minutes.

I was wondering if there was another way of handling this, for example
by triggering an immediate queue lookup from postfix or forwarding a
copy of the mail to the other server. Note that the postfix
"queue_run_delay" was increased to 15min on purpose, so I cannot change
that.

I'm using dovecot 2.0.15 on Debian Squeeze, kernel 2.6.32-5-amd64.

Thanks,

Alexis