Try to apply these patches to both proxy and backend and see what it logs then?
http://hg.dovecot.org/dovecot-2.0/raw-rev/1b1fc681a277 http://hg.dovecot.org/dovecot-2.0/raw-rev/36e7ded2ef0b http://hg.dovecot.org/dovecot-2.0/raw-rev/537d4b6d9a7a On Tue, 2011-06-28 at 08:38 +0000, Innocenzi, Cinzia wrote: > Hello Timo, > > so far I've seen this happening when proxying a mail for one recipient; I've > never seen this happening for multiple recipients. > > The other thing I've noticed is that if I reload dovecot, the mail usually > gets delivered. Once, it remained stuck in the queue, but after a few hours, > when I checked postfix's queue again, it got delivered. > > Let me know if you need further information. > > Regards, > > CINZIA INNOCENZI > Technical Consulting > HP Enterprise Services > Telephone +39 06.6542.5758 > Email cinzia.innoce...@hp.com > Via Achille Campanile, 85 / Rome, Italy 00143 > > > > -----Original Message----- > From: Timo Sirainen [mailto:t...@iki.fi] > Sent: martedì 28 giugno 2011 2.04 > To: Innocenzi, Cinzia > Cc: dovecot@dovecot.org; Del Coiro, Maria Giacinta > Subject: Re: [Dovecot] Dovecot 2.0.13 problem with LMTP > > On Wed, 2011-06-22 at 10:31 +0000, Innocenzi, Cinzia wrote: > > Hello, > > > > we have dovecot 2.0.13 installed in our RHEL5 servers. We use dovecot > > as a lmtp proxy on the front end mail relays and dovecot for back end > > lmtp/pop/imap. All our servers have RHEL5.6 64-bit and dovecot 2.0.13 > > installed, and the back end has also an ext3 mbox file-system mounted. > > > > Sometimes we have mails that get stuck on our postfix queue with the > > following error: Remote server not answering (timeout in DATA input) > > (in reply to end of DATA command) > .. > > It doesn't happen for every single mail, it's random. > > My guess is there's a bug somewhere in the LMTP proxy code. It's a bit > annoyingly complex code.. Do you see this happening when proxying only a > single mail (one RCPT TO per DATA, not multiple)? > > And I would guess that when attempting to deliver the same mail again it > works fine (at least in a few tries)? > >