LMTP-Process stays in RCPT TO state

[Stephan Bosch]

On 05/10/2019 13:01, Pascal Christen via dovecot wrote:
>
> Hi
>
>
> We tried to update our Dovecot Director-Ring to 2.3 (latest version) 
> and had one problem/bug. When we try to deliver an email from Exim to 
> a receiving Dovecot (2.3 latest) via the LMTP-Proxy the LMTP process 
> stays open forever and never closes. So after a few hours, we hit the 
> LMPT-Process limit.
>
> The problem only exists if the receiving Dovecot reports "Quota 
> exceeded (mailbox for user is full)" back to the Exim. If this is the 
> case the state on the LMPT process stays at "lmtp: [_IP_ RCPT TO] 
> (lmtp) and never closes. The TCP-Connection to the Exim is then in 
> CLOSE_WAIT state on the Proxy. On the receiving Dovecot we set the 
> "lmtp_rcpt_check_quota=yes" option. For me, it sounds similar to this 
> bug: https://dovecot.org/list/dovecot/2018-January/110697.html but 
> without the SEGFAULT which makes it harder to debug it.
>
> May you guys know why it doesn't change the state to IDLE or READY 
> after reporting the quota issue or see something fishy in the commit 
> above. If not I try to get a trace of the hanging process.
>
>
> Greetings Pascal
>

So far, I haven't been able to reproduce anything weird at this end. Can 
you provide:

- Output from `dovecot -n'
- Protocol logs from the connections between Exim and Dovecot 
director/proxy and between Dovecot director/proxy and Dovecot backend 
(e.g. using ngrep when connections are plaintext or using the rawlog 
facility).
- Dovecot debug logs produced with `log_debug=category:lmtp' for both 
director/proxy and backend

Regards,

Stephan.