[conspire] Postfix questions

Rick Moen rick at linuxmafia.com
Tue Dec 22 11:02:05 PST 2009

Quoting Ruben Safir (ruben at mrbrklyn.com):

> Ah - that is right.  You recommended exim.  Ach, I'm so stupid
> sometimes.

Well, it's more complex than that.  I think Postfix is arguably a better
MTA in one very fundamental aspect.  I just haven't yet learned its quirks.

I have material on this subject at

In brief:  Sendmail and Exim share the model of a monolithic binary
where each process instance drops privilege according to role.  Postfix,
Qmail, and Courier-MTA share a different design, where a number of
independent modules exist, each with appropriate privilege, and with
careful attention to inter-modular communication.

Most people would say the latter model is more likely, mutatis mutandis,
to result in a good security record.  (Qmail and Postfix implement the
modularity idea differently.  See my page for details.)

The area of MTA comparisons is nearly hopeless because it's polluted by
advocacy, which in turn results (at least in part) from the significant
pain of switching.  Which is why I attempted the nearly hopeless on the
cited page.  ;->

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