Mailman/Postfix and the dreaded group mismatch

Andrea D'Amore and.damore at
Fri Oct 8 05:25:04 PDT 2010

On Thu, Oct 7, 2010 at 8:08 PM, Bill Christensen
<billc_lists at> wrote:

> I'm using
> Fetchmail (MacPorts install) to retrieve the mail from the 3rd party server
> and deliver it to Mailman, and then sending out via the existing Postfix
> server.   The error I'm seeing when running Fetchmail is:

> fetchmail: IMAP> A0009 FETCH 2 BODY.PEEK[TEXT]
> Group mismatch error.  Mailman expected the mail
> wrapper script to be executed as group "_mailman", but
> the system's mail server executed the mail script as
> group "staff".  Try tweaking the mail server to run the
> script as group "_mailman", or re-run configure,
> providing the command line option `--with-mail-gid=staff'.
> fetchmail: IMAP< * 2 FETCH (BODY[TEXT] {25}
>  (25 body octets) *

>From what you write I'd say it's a fetchmail issue rather than a
mailman one, i.e. fetchmail is invoking mailman as part of its task
and is using a wrong gid, cf. <>

> I went into the Mailman portfile and added --with-mail-gid=staff to the
> configure, port uninstalled and reinstalled.  I'm still getting the same
> error.  Do I need to do something else to 'clean' the install of the old
> settings?

This seems wrong, did you put "--with-mail-gid=staff" before
You could be still replacing the option you just added, you'd better
edit the "set mmgroup mailman" line upward.

> Or do any of you know what to change on the Postfix end in order to "tweak
> the mail server to run the script as group '_mailman'?

I had a look at mailmain image, but I couldn't see any "mailman" group
in both LaunchDaemon plist or in the wrapper that is passed to
daemondo, can anyone explain how mailman.wrapper is normally run with
the correct gid?


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