Postfix w/ Maildrop

Postfix_w/o_Maildrop gives a working setup sans Maildrop - following that should give a working mail server, and Maildrop doesn't leave any cruft behind in the process.

Maildrop

apt-get install maildrop

At time of writing, the maildrop package in unstable is affected by bug #459545 maildrop: Tries to overwrite /usr/bin/makedat, which is also supplied by courier-base. Install maildrop from testing, and install it before Courier.

Configuration

Postfix

master.cf

/etc/postfix/master.cf should contain:

maildrop  unix  -       n       n       -       -       pipe
 flags=DRhu user=vmail argv=/usr/bin/maildrop -d ${recipient}

main.cf

/etc/postfix/main.cf should contain (among other things):

virtual_transport = maildrop

User tables

The records in the database have to be changed to make Postfix use maildrop as opposed to delivering the mail itself.

update postfix_transport set destination="maildrop:";

Maildrop

Useful reading for writing Maildrop filter files: maildropfilter man page

To make sure maildirs are created for new users, add to /etc/courier/maildroprc:

# Global maildrop filter file

# Uncomment this line to make maildrop default to ~/Maildir for
# delivery- this is where courier-imap (amongst others) will look.
#DEFAULT="$HOME/Maildir"

SHELL="/bin/bash"
logfile "/var/log/maildrop"
VERBOSE="5"
log "========"

MAILDIR = "$DEFAULT"

`test -f $MAILDIR/.forward`
if ($RETURNCODE == 0 )
{
        include "$MAILDIR/.forward"
}

`test -e $MAILDIR`
if ( $RETURNCODE != 0 )
{
`/usr/bin/maildirmake $MAILDIR`
`chmod -R 0700 $MAILDIR`
}

Testing for a .forward file, and including it if it exists, lets individual virtual users set maildrop rules.

Issues

Log file

If the log file specified in the maildroprc isn't created, or maildrop doesn't have the permissions to access it, this will appear in the logs:

status=deferred (temporary failure. Command output: /usr/bin/maildrop: Unable to create log file. )

Authdaemon

It looks like if the changes to authdaemon made before are reverted, Maildrop also gets broken, with the effect that messages get bounced:

status=bounced (user unknown. Command output: ERR: authdaemon: s_connect() failed: Permission denied Invalid user specified. )

Evidently this is a bad thing.