logging LMTP activity

[Janis]

On 2020.09.11. 20:49, Aki Tuomi wrote:
>> On 11/09/2020 20:30 Janis <dvml at abj.lv> wrote:
>>
>>   
>> Hello,
>>
>> I've been trying to set up Postfix + Dovecot LMTP setup. Basic idea
>> taken from https://wiki2.dovecot.org/HowTo/PostfixDovecotLMTP, but since
>> Postfix is on different host inet listener is used instead of unix socket.
>>
>> Message delivery works. Messages are delivered to correct mailboxes, if
>> they exist.
>>
>> But the problem is with logging on Dovecot side; i can not get any lmtp
>> logs at all. I kind of expected that i could get logs about:
>> 1) Postfix has connected and delivering mail to mail at address.com,
>> 2) If mailbox does not exists, would expect to see in logs the reason
>> for rejection - mailbox does not exist
>> 3) any other useful info would be nice as well.
>>
>> How do you get LMTP to log something? My Dovecot version is 2.3.11.3.
>> Basic IMAP logging is working. I see when users have connected, etc.
>>
>> I tried as suggested at
>> https://doc.dovecot.org/configuration_manual/protocols/lmtp_server/#logging
>>
>> If the given logging example block is used in configuration, i get no
>> logs in file /var/log/dovecot-lmtp.log. I thought maybe file is not
>> created automatically, so i tried to create it myself as well. Does not
>> work. chmod 0777 does not either, chown to dovecot:dovecot neither.
>>
>> In a way i am curious about "executable = lmtp -L" part. What is -L
>> flag? Are there any more flags? Where could i learn about them? I have
>> read all the docs that come with the buld and mention something of lmtp,
>> it's basically wiki, i guess... but i could not find any helpful info.
>>
>> I found that file lmtp is at /usr/local/libexec/dovecot/lmtp. When i
>> execute it with -L flag it works. Other flags don't. The problem is that
>> there are no -h or --help flags.
>>
>>
>> Then i tried raw logging as described here:
>> https://doc.dovecot.org/admin_manual/debugging/debugging_rawlog/#debugging-rawlog
>>
>> As i understand, only 4th possibility is applicable to LMTP, am i right?
>> 2nd kind of seems maybe somehow could be usable, but i don't see how...
>>
>> It is not clearly stated in wiki where "lmtp_rawlog_dir" should be
>> added, but i add it within "protocol lmtp { .. }" block, similar as
>> imap. Does not work for me - no logs while messages arrive.  The catchy
>> part in wiki is that for imap special arguments are used "-R rawlog" in
>> service imap-login, postlogin.  But i don't see any lmtp-login or such
>> service available. So should it work only with "lmtp_rawlog_dir" option?
>>
>> What could i be doing wrong?
>>
>> Does anyone have working lmtp configuration with logging available?
>>
>> Thank you very much! I am sorry that my message is so long, but i tried
>> even more to get it working... :)
>>
>> Any help or idea of how to better debug the situation or search for
>> solution is kindly appreciated.
> You could start with mail_debug=yes.
>
> Aki

Thank you for fast reply.

I have mail_debug=yes. Sorry, i did not sent my whole configuration, did 
not know which one since i tried many.

But i got an idea to use telnet, since LMTP is similar to SMTP. And 
Dovecot logs my telnet connection and rawlog as well. Thus Dovecot 
logging works. Which is good. Which means i have problem elsewhere, 
which is good as well, since i can move forward with the setup.

I guess it's case closed/solved.

Thank you.