INSTALL.mbox

The qmail package includes a local delivery agent, qmail-local, which
provides user-controlled mailing lists, cross-host alias loop detection,
and many other important qmail features.

There's one important difference between qmail-local and binmail:
qmail-local delivers mail by default into ~user/Mailbox, rather than
/var/spool/mail/user. It uses mbox format, with lockf locking on systems
that don't have flock (HP/UX, Solaris), and flock locking otherwise.

This file explains how to switch your system to ~user/Mailbox. You
aren't required to do this; for further discussion of /var/spool/mail,
and an explanation of how to continue using binmail for local
deliveries, see INSTALL.vsm.

The basic procedure for switching to ~user/Mailbox is simple:

   * Move each /var/spool/mail/user to ~user/Mailbox. For safety, do
     this in single-user mode.

   * As root, set up a symbolic link from /var/spool/mail/user to
     ~user/Mailbox for each user. /var/spool/mail should be mode 1777,
     so users will not be able to accidentally remove these links.

A few mail programs are unable to handle symbolic links, so you will
have to configure them to look at ~user/Mailbox directly:

   * procmail: Change SYSTEM_MBOX in config.h and recompile; or, with
     recent versions, define MAILSPOOLHOME in src/authenticate.c.

An alternative to symbolic links is hlfsd. Consult the documentation for
hlfsd if it is included in your operating system.

If /var/spool/mail is large, you can gain extra speed by configuring
all your mail software to look at ~user/Mailbox directly:

   * Most MUAs: Put ``setenv MAIL $HOME/Mailbox'' in your system-wide
     .cshrc and ``MAIL=$HOME/Mailbox; export MAIL'' in your system-wide
     .profile.

   * elm: Change "mailbox" to "Mailbox" around line 388 of newmbox.c and
     recompile. (elm looks at $MAIL, but without this change elm will
     fail if two users try to read mail simultaneously.)

   * pine: Put ``inbox-path=Mailbox'' in your system-wide pine.conf.
     (For pine versions more recent than 3.91, see also FAQ 6.2.)

   * qpopper 2.2: Change /.mail to /Mailbox in pop_dropcopy.c and
     recompile with -DHOMEDIRMAIL in CFLAGS.

Some vendors, in a misguided attempt to solve the security problems of
/var/spool/mail, have made all their mail software setgid mail. After
you move the mailboxes, you can---and, for security, should---remove
those setgid-mail bits.