[Techtalk] Sendmail to Postfix

Dominik Schramm dominik.schramm at gmxpro.net
Sat Dec 13 21:28:49 EST 2003

Hi Raquel,

On 12/13/2003 06:52 PM, Raquel Rice wrote:

 > I started out man years ago with RedHat 6.2 and just recently set up
 > a new server with Debian/Woody. I love that it's rock-solid and I'm
 > falling in love with apt-get/aptitude.

Same thing happened to me. :-)
But I also liked dselect, which so far has caused most of my colleagues 
and friends
to run away and hide.

 > I guess that when looking at the different MTAs I kind of got lost
 > in all the features and advantages. I couldn't figure out what
 > advantages Exim had over Postfix.

Okay, I don't want to start off the holy war over exim vs. postfix
on this list, so I won't enumerate any advantages.

Basically, I installed postfix once three years ago. It was okay
for the purpose then. I encountered it again half a year ago
and I was supposed to configure it so that it would send a
message to some alternate recipient in addition to the original one.
This couldn't be done. In exim it was done within two minutes.

I'm not a postfix expert, but *I think* exim is much more flexible:
you can have many configuration items in separate files or in a database,
you can use regular expressions extensively, you can even run
exim with an embedded perl interpreter. There is a patch called
exiscan, which can be used to scan messages (for viruses, for spam
indicators...) at almost any stage in the receiving process.
You can run external programs if you find that exim is not good
enough to do mail delivery, routing decisions, etc. (basically all
"string expansions").
New to exim 4 are the so called acl's: you can configure exim to
reject or accept messages based on e.g. where the mail comes from,
what letters the recipient name contains etc.

*However*: the flexibility also means that you probably have to
consider many more details if something doesn't work (compared to
postfix). That's why I said that you could give exim a try
if MTA functionality is a *major concern*, i.e., if you may
have to implement complicated scenarios (the ones that grow
over time and are not based on a clear blue-print)
which may change radically over time. (Such are the conditions
in the company I work for.)

Plus there is plenty of documentation (also a kind of cookbook)
out there. But this seems to be the case for postfix, too.

The main *disadvantage* of Debian+exim is that Debian Woody
still contains exim version 3.3x (thirty-six, I think); for this version 
get no (or only very reluctant) support on the mailing lists.
If you want to start using exim, I recommend starting with the
current release 4.30, because the configuration changed significantly
from 3.36 to 4.0.
This disadvantage will disappear as soon as exim 4.x is part of the stable
release, which can't be that long.

If you find someone you trust who tells you to use postfix
because it is better for your purposes, then use postfix!

Did this answer your question? :-)

kind regards,

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