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 part of qmail-local that you need to know about right now:
qmail-local delivers mail by default into ~user/Mailbox (in mbox format,
using flock), rather than /var/spool/mail/user.

For an explanation of the problems with /var/spool/mail, and a list of
options if you want to continue delivering to /var/spool/mail, see
INSTALL.vsm.

This file explains how to handle the change to ~user/Mailbox. The basic
procedure 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.

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
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.)

   * procmail: Change SYSTEM_MBOX in config.h and recompile.

   * 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.