When a yum update sets up an MTA ...

[Lars Seipel]

Nicely aligning with the current firewall thread I noticed that one of
my machines was running the exim MTA for the last few days, dutifully
listening on all interfaces.

How did this happen? It turns out that smartmontools intermittently
required 'MTA' which (presumably due to its nice and short name) pulls
in exim when there's no MTA already installed. This dependency was
replaced (with a file dep on %{_sbindir}/sendmail) in
smartmontools-6.2-5.fc20.

Ok, that's how it got installed. But why does it get run? Is the
installation of exim tricking my system into believing it's Debian?

We do have the presets functionality[0] for this, I thought. And indeed,
a call to systemctl preset disables exim.service just like it's supposed
to do.

Looking at exim's spec file shows its %post is using the proper
systemd_post macro which honors presets. In %postun, though, there's a
direct call to systemctl enable, buried in the sysv conversion stuff. Is
it really supposed to be there? But this shouldn't get executed on
package install anyway, right?

Would be glad if someone who knows a bit more about the interaction of
RPM and systemd preset files could chime in and tell me where the bug
report should go.

Lars

[0] https://fedoraproject.org/wiki/Features/PackagePresets