Issue with LMTP proxying and port number

[Stephan Bosch]

Op 06/01/2019 om 17:05 schreef Stephan Bosch:
>
> Op 31/12/2018 om 06:32 schreef Laz C. Peterson:
>> Hello Sami, yes, see below.
>>
>> We run Dovecot at a different versions, mainly 2.2.10 (CentOS), 
>> 2.2.22 (Ubuntu) and now 2.2.36 (CentOS).  The issue is weird, because 
>> it only happened after the update from 2.2.10->36.  Just to 
>> understand it would be great.
>>
>> I'm actually checking out the configs now ... Our SQL userdb does not 
>> specify port.  So I'm guessing this may be to blame?
>>
>> (This was by design, though -- we don't want to specify one port for 
>> different client protocols.  Though, I do recall seeing some hack 
>> online using CASE in SQL query ...)
>>
>> These servers run LMTP as a unix socket as well as a TCP port 24 
>> serving all IP sources.  The internal servers are running LMTP on TCP 
>> port 24 (as well as unix socket, but that's irrelevant), but no LMTP 
>> comm happens between directors and backend mail servers after the 
>> 2.2.10->36 update on the directors with our config.  I do apologize 
>> that I can't get more specific than those versions ...
>>
>> The backend mail servers function the same in our environment on both 
>> versions 2.2.10 and 2.2.36.
>>
>> We are good now, as we changed the config to go to the TCP port 
>> instead of unix socket.  But we had a good jolt of fun this morning. :-)
>>
>> Would love to understand what we have done wrong, or how we 
>> misunderstood the configuration directives -- in either version.
>
> I can reproduce it here, even with master.
>
> We'll get back to you.
>
> BTW, similar thread here:
>
> https://www.dovecot.org/pipermail/dovecot/2019-January/114071.html

Hmm, did you try returning a protocol=lmtp field from passdb? This is 
ignored by services other than lmtp and the code tells me it will then 
default to port 24. That should be a workaround.

Regards,

Stephan.