Re: How to add support to OpenSMTPD to distinguish between MTA and MSA operation mode?

On 01.09.24 15:39, Kirill A. Korinsky wrote:
> On Sun, 01 Sep 2024 13:12:19 +0200,
> Christian Schulte <schulte.it@gmail.com> wrote:
>>
>> I just started to read OpenSMTPD sources. Regarding the latest
>> discussions on tech@, there maybe seems to be the need to instruct
>> OpenSMTPD listeners to behave differently when acting as MTA or MSA.
>> Reading man smtpd.conf(5)[1] there is an option to add a tag to the
>> "listen on [socket]" directive. Those tags are currently used in "match"
>> directives. Maybe this could be extended to add well known tags to a
>> listener to control operation modes like MTA or MSA. Both of this is
>> documented in corresponding RFCs. Is there any interest for me to take a
>> closer look any maybe come up with some patches tech@? I am really just
>> starting to read OpenSMTPD sources. If there already is a way to
>> instruct OpenSMTPD listeners to behave differently regarding to - for
>> example - handling message ids based on in either MTA or MSA mode,
>> please let me know. I would like to avoid spending time into this, if
>> there is no interest but I think there really should be a way to
>> configure listeners to specific operation modes like MTA or MSA.
>>
>
> As far as I know and had discovered by reading sources the specified
> behaviour for the MSA like adding Message-Id is triggered only when listener
> is used submission port.
>
> So, simple use submission port and that's it.
>
> P.S. I think that misc@opensmtpd.org is the right misc@ for this email.
>

Thinking out loud now. If OpenSMTPD does something based on the port
configured, I would rate that utterly workaround. I am thinking about
adding support for something like this.


listen on ... mode mta
listen on ... mode mta-accurate
listen on ... mode msa
listen on ... mode msa-accurate

Maybe someone wants to s/accurate/pedantic/g. But that's a language thing.

mode mta

Default mode, when no mode is given in the configuration file. Without
any logic about ports. Just transport the message. Even if it contains a
message id <nospam@nospam>.

mode mta-accurate

Would refuse to accept any mails without a (valid) message id. Permanent
failure. "No message id or message id invalid" right now lacking a
definition of invalid but that is documented in various RFCs.

mode msa

Check validity of the message id. If not present, add a message id. If
not valid, overwrite it silently with something sane.

mode msa-accurate

Check validity of the message id. If not present, add a message id. If
not valid, permanent failure.

--
Christian