dovecot - Apr 2021 - debug SMTP commands sent/received to/from the submission service

Dear Colleagues,

I'm trying to debug SMTP commands clients send to the submission
service. 

I've tried 

protocol submission {
  rawlog_dir = /var/tmp/dovecot
}

but /var/tmp/dovecot remains empty. What am I missing? I'd use Wireshark
but the communication between SMTP clients and Dovecot is encrypted
after STARTTLS, so Wireshark is pretty useless here.

Can you please point me to the right direction to log all SMTP commands?
All is happening on Debian/buster, Dovecot 2.3.4.1.

-- 
Victor Sudakov VAS4-RIPE
http://vas.tomsk.ru/
2:5005/49 at fidonet
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> On 09/04/2021 10:13 Victor Sudakov <vas at sibptus.ru> wrote:
> 
>  
> Dear Colleagues,
> 
> I'm trying to debug SMTP commands clients send to the submission
> service. 
> 
> I've tried 
> 
> protocol submission {
>   rawlog_dir = /var/tmp/dovecot
> }
> 
> but /var/tmp/dovecot remains empty. What am I missing? I'd use
Wireshark
> but the communication between SMTP clients and Dovecot is encrypted
> after STARTTLS, so Wireshark is pretty useless here.
> 
> Can you please point me to the right direction to log all SMTP commands?
> All is happening on Debian/buster, Dovecot 2.3.4.1.
> 
> -- 
> Victor Sudakov VAS4-RIPE
> http://vas.tomsk.ru/
> 2:5005/49 at fidonet

> On 09/04/2021 10:13 Victor Sudakov <vas at sibptus.ru> wrote:
> 
>  
> Dear Colleagues,
> 
> I'm trying to debug SMTP commands clients send to the submission
> service. 
> 
> I've tried 
> 
> protocol submission {
>   rawlog_dir = /var/tmp/dovecot
> }
> 
> but /var/tmp/dovecot remains empty. What am I missing? I'd use
Wireshark
> but the communication between SMTP clients and Dovecot is encrypted
> after STARTTLS, so Wireshark is pretty useless here.
> 
> Can you please point me to the right direction to log all SMTP commands?
> All is happening on Debian/buster, Dovecot 2.3.4.1.
> 
> -- 
> Victor Sudakov VAS4-RIPE
> http://vas.tomsk.ru/
> 2:5005/49 at fidonet
Sorry for sending empty mail first...

I would recommend using

   rawlog_dir = /var/tmp/dovecot/%u

and then ensuring that the directory, which expands to the username, *exists*
and is *writable* to your mail user. Dovecot will not attempt to create this
directory.

Aki

On 09/04/2021 15.13, Victor Sudakov wrote:
> I'd use Wireshark but the communication between SMTP clients and
Dovecot is encrypted
> after STARTTLS, so Wireshark is pretty useless here.
You might get some useful information connecting with openssl s_client

Here's a page googled at random.
https://halon.io/blog/how-to-test-smtp-servers-using-the-command-line/

And man page.
https://linux.die.net/man/1/s_client

P