Dovecot LMTP dropping connection after first part of multipart message received

John Fawcett john at
Thu Dec 10 18:15:04 EET 2020

On 10/12/2020 14:58, Steve Akerman wrote:
> Good afternoon
> I have been using Dovecot with great success for several months now
> with one problem:
> I have received several messages (3 to date out of a much larger
> number) which cause Dovecot LMTP to drop the connection with sendmail
> after only receiving the first part of the message.
> Dovecot saves the first part to INBOX, and then drops the link with
> sendmail as it sees the rest of the data from sendmail as new (and
> invalid) commands
> Sendmail sees the delivery as unsuccessful and requeues the message,
> so the cycle continues until i kill the queue
> These messages are all Multipart MIME
> I have attached an extract from the log which shows the above sequence
> Finally, I have kept one such message from the sendmail queue (df and
> qf) should this be useful, but prefer not to post here as not sanitised 
> Any help in correcting my configuration would be appreciated.
> Thanks
> Steve
> <snip>
Hi Steve

strange as it sounds, looks like your mta is sending the lmtp end of
message sequence (<CRLF>.<CRLF>)in the middle of an email.

You might be able to debug it in dovecot with lmtp_rawlog_dir setting
which will show the input and output dialog of the lmtp session.


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