maildrop for Debian
-------------------

Using maildrop per-user
-----------------------

You should be able to run maildrop without making it your default system
MDA: just put "|/usr/bin/maildrop" in your ~/.forward file (including the
quotes).

Using maildrop system-wide
--------------------------

Here's a short recipe on how to set it as a MDA in Exim's exim.conf:

Add this to the transports section (anywhere, order doesn't matter):

maildrop_pipe:
  driver = pipe
  command = "/usr/bin/maildrop"
  user = $local_part
  group = mail
  return_fail_output
  return_path_add
  delivery_date_add
  envelope_to_add
  check_string = "From "
  escape_string = ">From "

Notice that Exim has its own user/group setting mechanism so you don't have
to utilize the -d option for maildrop (-d $local_part in this case).

Add this to the routers section (at the end, order does matter):

maildrop:
  driver = localuser
  transport = maildrop_pipe
  require_files = ${local_part}:+${home}:+${home}/.mailfilter:+/usr/bin/maildrop
  no_verify
  headers_add = "Delivered-To: ${local_part}@${domain}"

Note that Exim 3.x calls the latter section "directors" rather than "routers".

Note also that the return_fail_output is much preferred over return_output,
because maildrop will return a verbose message when encountering a temporary
error message.

That's it. It's not the only way nor the guaranteed correct way to make it
work, but It Works For Me (TM) :)

For Postfix, you should be able to make it work just by adding the following
line to your /etc/postfix/main.cf file:

mailbox_command = /usr/bin/maildrop

Notice that Postfix also has its own user/group setting mechanism so you
don't have to utilize the -d option for maildrop (-d ${USER} in this
case).

More information should be available at
http://www.postfix.org/MAILDROP_README.html

For Sendmail, it should be possible to use maildrop as a system-wide MDA
by adding the following to your /etc/mail/sendmail.mc file:

FEATURE(`local_procmail', `/usr/bin/maildrop', `maildrop -d $u').

The same note about -d option applies as above; if Sendmail has a way of
running maildrop with amended user data, that can be used instead of -d.

Note also that maildrop 2.x with the Courier authlib plugin will also try to
contact the Courier authdaemon when maildrop is invoked with the -d option.
Failure to contact it will not be treated as a temporary error unless the
-a option is also specified.

Alternatives mechanism
----------------------

Note that lockmail, maildirmake and deliverquota and the accompanying manual
pages have been renamed to include the ".maildrop" suffix, in order to avoid
conflicts and allow coexistence with courier (lockmail, maildirmake,
deliverquota), qmail (maildirmake) and potentially others. Alternatives
(symlinks) have been used instead, so you can choose which of the programs
you want to use by default, using update-alternatives.

Privileges
----------

maildrop and lockmail.maildrop are installed setgid mail so that they can
do mailbox locking in the /var/mail directory. setuid root is removed
intentionally, you shouldn't ever really need it and it poses a potential
security risk (as any other suid binary).

The go-r restriction on .mailfilter* is removed in the Debian package;
the restriction that files may not be writable by the world remains.

 -- Tommi Virtanen,  Tue,  8 Sep 1998 12:01:27 +0300
 -- Josip Rodin,  Sun, 10 Sep 2006 12:16:15 +0200