sendmail configuring port numbers

[Ben Scott]

On Tue, Oct 13, 2009 at 4:40 PM, Steven W. Orr <steveo at syslang.net> wrote:
> The list manager running on "A" was configured to send to localhost:24 ...

  Why?  :)

> I did this by setting:
> define(`confMAX_RCPTS_PER_MESSAGE', `20')dnl
> which for me makes sense. (Am I wrong?) :-(

  Well, that means Sendmail will reject envelopes with more than 20
recipients.  Which means you won't be able to send or receive messages
with more than 20 recipients.  Since you later go on to complain about
that limitation, I'm guessing it's wrong.  ;-)  Read on for more.

> * I want submit.mc to listen on port 25 and port 24 of localhost.

  I'm pretty sure you *don't* want that.

  Don't dick around with submit.mc unless you *really* know what
you're doing.  Now, I myself don't really know what I'm doing when it
comes to this aspect of Sendmail, so I've steered clear myself.  My
limited understanding is:

  submit.mc builds submit.cf, which is used by Sendmail when running
in MSP (Mail Submission Program).  MSP mode is used when
/usr/bin/sendmail is invoked by local programs to submit mail into a
mail queue.  It doesn't listen on any ports and doesn't run as an SMTP
MTA.  It's part of a privilege separation mechanism and is basically a
Sendmail internal.  Here there be dragons, etc.

> Am I trying to do something that is a good idea?

  Possibly not a good idea.

  All the SMTP standards -- RFC-821, RFC-2821, and RFC-5321 -- say you
MUST accept a minimum of 100 recipients.  If you want to go ahead and
reject on fewer, I don't know what will happen, but since you're
technically violating the standard, beware of nasal demons.

http://tools.ietf.org/html/rfc5321#section-4.5.3.1.8

  I honestly don't know.  Sometimes standards get things wrong or lag
behind reality.

> Can someone tell me how to do it if it is?

  I'll ignore the question of whether it's a good idea or not for
purposes of discussion.  :)

  confMAX_RCPTS_PER_MESSAGE just defines the Sendmail option
"MaxRecipientsPerMessage".

  I think the only way to have a multiple sets of Sendmail options is
to run another instance of Sendmail.  That would involve, at a
minimum, another config file (.cf) and another queue directory.
Presumably another macro config file (.mc) to build the config file.
Possibly another MSP to go with it, which would also be another set of
files and another config file.

  Keep in mind that I'm far from a Sendmail expert.  There may be a
more efficient way to do this, e.g., some way to apply
MaxRecipientsPerMessage to a DaemonPortOptions instance, rather than a
whole 'nother Sendmail instance.  But I don't know of one.

-- Ben