Default-installed MTA (was Re: MTA virtual provides craziness)

Lennart Poettering mzerqung at
Wed May 15 14:30:35 UTC 2013

On Wed, 15.05.13 09:08, Chris Adams (linux at wrote:

> Once upon a time, Dan Mashal <dan.mashal at> said:
> > Sanity: Switching to postfix?
> That's a long-time sore point, but the general idea is that "sanity" is
> not switching desktops/non-mail-servers from one full-featured MTA to
> another.  The right move is to either remove a local MTA from the
> default install (which I think has been worked on), or switch to a
> light-weight daemon that is a local queue-and-forward mail handler.
> The downside of that would be that configuration of an upstream mail
> server (possibly requiring SSL and/or authentication) would be required
> for it to work, while sendmail/postfix/etc. can actually deliver
> messages (modulo other servers' spam filtering) in the default config.

I am pretty sure that the big majority of mail servers on the internet
still accept mails from servers in this default mode.

An unconfigured mail server doesn't really do anything good. And stuff
that needs configuration before being useful shouldn't be in the default

> The core problem is that there's a general long-time Unix assumption
> that piping something to /usr/sbin/sendmail and/or connecting a TCP
> socket to localhost:smtp can send email, and so many things don't
> explicitly specify that need.  The idea is that /usr/sbin/sendmail
> handles connecting to the "right" host, aliasing, etc.
> Just to pick an example: mdadm (for Linux software RAID) has a monitor
> mode to notify somebody of disk failures.  Failures would already go in
> the system log (from the kernel); running mdadm --monitor is for sending
> a more active notice.  It is possible for mdadm to run an external alert
> program; on a desktop, that could use the system bus to notify the
> logged-in user.  How do you handle a headless system, a desktop with
> nobody logged in, etc.?  The only standard way to notifiy somebody off
> the box is SMTP (I suppose mdadm could use SNMP traps, but that's even
> more work to configure correctly).

I'd suggest that mdadm should do what cronie already does these days:
try to use sendmail if it's there and only then, and unconditionally log
things to syslog. This would the allow us to remove an SMTP server from
the default install, and everything would appear in the logs just
fine. And as soon as the admin decides to install a mail server and
configure it then he will get mails too.

That would allow people who want everything via logs to get everything
via logs. It would make our basic installed set smaller, and boot-up
faster. And people who want a mail server can just install one and
configure it and things will be magically hooked up with everything else.


Lennart Poettering - Red Hat, Inc.

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