[Mailman-Users] Virtual Domain Hosting

Stephen J. Turnbull stephen at xemacs.org
Thu Oct 11 18:29:01 CEST 2012

P.V.Anthony writes:

 > Is this true for all versions of mailman?

All versions so far released by this project, yes.  cPanel and maybe
some other third-party distributions have patched versions of Mailman
that allow one instance of Mailman to handle multiple domains with
independent namespaces for lists.  The patch is a kludge, not easy to
get your hands on, and cPanel Mailman itself is a high price to pay
(once you mention cPanel, you have to put up with references to the
FAQ explaining why we often can't help with cPanel problems in every
reply you get, and you probably lose a lot of people who wold
otherwise be helpful as soon as you mention cPanel).

There's another third-party patch, I believe; probably mentioned in
the FAQ somewhere.  Also a kludge, which looks fragile and has not
been proved in heavy testing in practice (it's actually not as common
a need as you might think, what with hosting on virtual machines).  So
despite occasional requests, it has never been added to the Mailman 2
distribution (the developers would rather devote the effort to Mailman

Speaking of which ... the virtual domain issue will be dealt with
differently in Mailman 3.  The whole infrastructure for dealing with
lists and with users has been redesigned from the ground up.  But
Mailman 3 is most likely not ready for you -- come back in about a

 > So there is no way to have mailling list called support at example.com and 
 > support at example_two.com on the same server.

That's right.  However, here, "server" refers to a set of OS processes
and its associated metadata.  You can serve multiple domains from a
single *host* without worrying about namespace collisions, by keeping
multiple installations of Mailman, one for each domain, and starting a
new set of processes to serve each one.

It might even be possible to have a single shared instance of Mailman,
and arrange that host configuration data be private to each Mailman
process.  But that would be a little fragile, I think, and might
require minor code changes.

I would guess it probably scales to a few-score domains on the same
hardware that would adequately support a given number of lists.  The
common case of a single server supporting a commercial domain and an
open source domain for users without support contracts would be no
sweat for this setup, even if you have a couple of products with their
own domains.


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