Magical Postfix Virtual Domains & Mailman

Since google helped me very little in tracking this down, I'm going to blog about it in the hopes it will save someone else pain :)

If you are trying to use a virtual domain with the postfix mailman transport to do mailman lists in a nice way, there is a bug in the pre-configured transport of postfix in Ubuntu Breezy (see debian bug 315939 that causes it to not work, resulting in these error messages

Feb 5 06:47:36 localhost postfix/pipe[15656]: fatal: service mailman requires privileged operation
Feb 5 06:47:37 localhost postfix/master[8847]: warning: process /usr/lib/postfix/pipe pid 15656 exit status 1
Feb 5 06:47:37 localhost postfix/master[8847]: warning: /usr/lib/postfix/pipe: bad command startup -- throttling

The fix is a simple modification to /etc/postfix/master.cf, it currently looks like

mailman unix - - n - - pipe
flags=FR user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py
${nexthop} ${user}

You want to change the 4th '-' to a 'n' like so

mailman unix - n n - - pipe
flags=FR user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py
${nexthop} ${user}

And then it works :)

For documentation on the whole process, read /usr/lib/mailman/bin/postfix-to-mailman.py