[Mailman-Users] MTA only for Mailman

Brad Knowles brad at stop.mail-abuse.org
Thu Jul 27 22:21:19 CEST 2006

At 10:58 AM -0600 2006-07-27, Ivan Fetch wrote:

>     Is anyone using a light weight MTA to just hand emails off to Mailman
>  and deny anything else?

The issues here are that you need to have certain features in your 
MTA in order to get that to work well with Mailman, such as a 
mechanism for adding aliases or some other method of identifying to 
the MTA which mailing lists are in existence and how to deliver mail 
to the appropriate addresses for each, etc....

In essence, this means that you can use a lighter-weight MTA than a 
more standard MTA sendmail, postfix, or Exim, but if you go that 
direction then you're going to be on your own.  Alternatively, you 
could use sendmail, postfix, or Exim, and just not use those other 
features of the program that you don't need.

>     I'm looking at Sun Sendmail (I know, it's definitely not light weight)
>  to do this, simply because it's already on the boxes in question - I'm
>  still sorting out how to get Sendmail to deliver to aliases, but not local
>  accounts.

Sendmail, postfix, and Exim are the three MTAs that integrate most 
naturally with Mailman.  On python.org (where the mailman-users 
mailing list is hosted, among many others), we currently use postfix. 
So, we can pretty much guarantee that the integration there is going 
to work well.

I've been involved in the postfix community for many years (since the 
days it was called VMailer), and I can tell you that Wietse has done 
a lot of things that make postfix a good MTA to use out-of-the-box 
for mailing lists.

I can also say that postfix is one of the very few programs I know of 
that can have a truly useful configuration file that is just two or 
three lines long, with everything else being taken from built-in 

Many people in the community also use sendmail, and the integration 
there is also pretty good -- that is, assuming you're running a 
pretty standard source-based install, because most vendors do some 
pretty heavy (and weird) customization of sendmail to work "better" 
in their environment.

Now, it turns out that John Beck is a longtime member of the Sendmail 
Consortium (the group that supports the open source version), and has 
been "the sendmail guy" at Sun for many years, and he's been working 
to get all those bizarre Sun-isms eliminated from the version they've 
been shipping.  Still, there are some oddities that have remained.

Your choices there are to either install the source-based version of 
sendmail and get that configured to work in your environment, or 
figure out what needs to be done to the Sun version in order to get 
it to work well with Mailman.

 From an objective viewpoint, it takes more work to get sendmail 
configured to work well for mailing lists than it does to get postfix 
configured to serve that same environment, but if you're more 
familiar with sendmail then it may be less work to stick with that 
than to try to rip that out and replace it with a completely 
different package.  It will also take more work to maintain sendmail 
suitably in this kind of environment as compared to postfix, but if 
you're doing lots of mail filtering (e.g., anti-spam or anti-virus 
processing), then you reach a point where sendmail will scale and 
perform better than postfix on the same hardware.

I can't speak too much for Exim, although I know a number of people 
in the Exim community make use of Mailman, and they've made it pretty 
easy to set things up so that you never need to update the aliases or 
anything in order to get the two working together.  I can tell you 
that Exim is pretty different from either sendmail or postfix, and if 
you've been used to using one of those two packages then it may take 
you some time to warp your mind around the Exim way of doing things.

That said, I know that Exim is an excellent MTA if properly 
configured, and is perfectly suitable for use with Mailman.

>  Thanks for any feedback on MTAs, or a more sensable way to accomplish
>  this.

Not knowing anything more about your environment, I'd guess that it 
should be pretty easy to get postfix installed and configured for 
your system, and we know that it integrates well with Mailman.

IIRC, pretty much all these issues are covered in the archives, and 
they should also be covered in the FAQ.

Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

  Founding Individual Sponsor of LOPSA.  See <http://www.lopsa.org/>.

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