Q: Mailman does not work with Postfix, complaining about GID
mismatch
A: Mailman uses a setgid wrapper that is designed to be used in
system-wide aliases file so that rest of mailman's mail
handling processes will run with proper uid/gid. Postfix has an
ability to run a command specified in an alias as owner of that
alias, thus mailman's wrapper is not needed here. The best
method to invoke mailman's mail handling via aliases is to use
separate alias file especially for mailman, and made it owned
by mailman and group mailman. Like:
alias_maps = hash:/etc/postfix/aliases,
hash:/var/mailman/aliases
Make sure that /var/mailman/aliases.db is owned by mailman user
(this may be done by executing postalias as mailman
userid).
Next, instead of using mailman-suggested aliases entries with
wrapper, use the following:
instead of
mailinglist: /var/mailman/mail/wrapper post mailinglist
mailinglist-admin: /var/mailman/mail/wrapper mailowner
mailinglist
mailinglist-request: /var/mailman/mail/wrapper mailcmd
mailinglist
...
use
mailinglist: /var/mailman/scripts/post mailinglist
mailinglist-admin: /var/mailman/scripts/mailowner
mailinglist
mailinglist-request: /var/mailman/scripts/mailcmd
mailinglist
...