Maildrop-Extension

Eventually your sources.list needs to be updated according to your needs. When done go the directory /usr/src and run the following commands. To make sure your package list has the latest information:

syscp ~ # apt-get update

When updated you can get the sources by running:

syscp ~ # apt-get source courier-maildrop

syscp ~ # apt-get build-dep courier-maildrop

First command gets the source of maildrop being stored in the directory /usr/src/courier-<version>. Second command makes sure all packages needed to compile maildrop will be installed and configured.

Its time to copy the patch into the directory /usr/src. The patch changes two elementary settings in the Courier-Maildrop-Package.

You can find the patch here. To apply the patch run the following command in the directory /usr/src

syscp ~ # patch -p0 < maildrop_mysql-sarge.patch

There are two different patch files we might need.

Maildrop is now patched and ready to compile. To compile Courier-Maildrop run the following command in /usr/src:

syscp ~ # apt-get source courier-maildrop -b

Since the sources are already present and unpacked, Debian will skip this step and starts with configure followed by a compile. Unfortunately the whole Courier-system is compiled, not only maildrop. Therefore we get more than one .deb-Files at the end.

Of course our maildrop also has to be installed. In the same directory as before /usr/src run the following command:

syscp ~ # dpkg -i courier-maildrop<version>.deb

Additionally, after installation the system has to be informed not to upgrade in case of a apt-get upgrade since we are using a patched package

syscp ~ # echo courier-maildrop hold | dpkg --set-selections

The hold-status can be switched by

syscp ~ # echo courier-maildrop install | dpkg --set-selections

To verify your settings use

syscp ~ # dpkg -l courier-maildrop

Below is an example for an output, given by the above verification-command

Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Installed/Config-files/Unpacked/Failed-config/Half-installed
|/ Err?======(none)/Hold/Reinst-required/X=both-problems (Status,Err: uppercase=======bad)
||/ Name           Version        Description
+++-=======-=======-============
hi  courier-maildr 0.47-4         Courier Mail Server - Mail delivery agent

Reading the first character will inform you about the status. Character h stands for hold and confirms that this package is not being upgraded automatically.

To avoid a termination with error code Signal 0x0B the configuration-file must be created now. Here you find an example of a typical configuration file.

/etc/courier/maildropmysql.config

hostname                localhost
socket                  /var/run/mysqld/mysqld.sock
port                    3306
database                syscp
dbuser                  syscp
dbpw                    SYSCPPASSWD
dbtable                 mail_users
default_uidnumber       2000
default_gid             2000
uid_field               email
uidnumber_field         uid
gidnumber_field         gid
maildir_field           maildir
homedirectory_field     homedir
quota_field             100000000
#quota_field            quota
# unused for now, but needs to be a valid field.
mailstatus_field        postfix
where_clause            AND postfix = 'Y'

The privileges of this files are recommended as 600. Keep in mind that it contains the password for syscp.

In order to give a detailed instruction of operation for maildrop we need the file /etc/courier/maildroprc which contains these instructions. This script forwards the mail to the virus-scanner or spam-filter and checks for results. Use the script from here and adapt the configuration of it to your needs:

/etc/courier/maildroprc

[...]
#Configuration
#########################################################
# set this to 1 if you want to log the usersettings vor vscan, etc.
LOGUSERSETTINGS=0

# Full path to the maildrop log of each user
LOGFILEPATH=$HOME$DEFAULT/maildrop.log

# Setting for SysCP maildrop module
USESYSCPSETTINGS=0


# Basedir of your syscp installation
SYSCPBASEDIR="/var/www/syscp"

# Default setting for the spamfilter
SPAMFILTER=0

# use spamc instead of the direct call to spamassassin
USESPAMC=1

# Default setting for the virusscan
VSCAN=0

# include userdefined filters into maildrop
USERFILTER=0

# basedir of your userdefined filterfiles
MAILFILTERDIR="/var/kunden/mailfilter"

# Only scan mails smaller than SCANSPAMSIZE for spam
SCANSPAMSIZE="2000000"

# Only scan mails smaller than VSCANSIZE for a virus
VSCANSIZE="2000000"
[...]

You may use the variable SPAMFILTER for a default activity of the spam-filter, where a value of 1 activates and a value of 0 deactivates the filter. Likewise the same applies to VSCAN which controls the behaviour of the virus-scanner. In case the SysCP-module for maildrop is installed, the value of USESYSCPSETTINGS can be set to 1 to engage a retrieval for virus-scanner / spamfilter from the SysCP database.

To let postfix know, that mails are forwarded to maildrop instead of using the own virtual-daemon the adjustments below need to be done. The value of the variable virtual_transport will be switched from virtual into maildrop

/etc/postfix/main.cf

[...]
virtual_gid_maps = mysql:/etc/postfix/mysql-virtual_gid_maps.cf
#virtual_gid_maps = static:2000

# use this for virtual delivery 
#virtual_transport = virtual
# use this for maildrop-delivery 
virtual_transport = maildrop

#Maildrop-Options for usage with maildrop
maildrop_destination_recipient_limit = 1
maildrop_destination_concurrency_limit = 1
[...]

Postfix also needs to know where exactly the target maildrop is located. It will be done by an adjustment of the file /etc/postfix/master.cf. The original file should already contain an commented out line for maildrop.

Please note the whitespaces in the second line. Postfix is quite sensitive regarding the syntax of master.cf

Once again we also like to point out: Don't use Windows - Editors (e.g. Notepad.exe)

/etc/postfix/master.cf

[...]
maildrop    unix    -    n    n    -    -    pipe
    flags=R  user=vmail argv=/usr/bin/maildrop -d ${recipient}
[...]

For installation and configuration of Spamassassin please refer to the countless HowTos you can find on the Internet. For an operation with maildrop a default installation is sufficient. It is up to you, if you prefer further filter, rules and plugins.

The current configuration here can be chosen to operate either with spamc or spamassassin. If you have a close look into /etc/courier/maildroprc you'll find xfilter-lines. Some users have reported that spamd will not start. By default spamd is deactivated. Therefore it has to be activated. Once again a small change to a configuration-file must be done.

In case you want to use maildrop in conjunction with spamc, the options have to be adjusted as well, because spamd must run as user vmail, otherwise no access to the settings in /var/kunden/mail is possible.

/etc/default/spamassassin

[...]
# Change to one to enable spamd
ENABLED=1
[...]
# Default options for use with spamassassin
#OPTIONS="--create-prefs --max-children 5 --helper-home-dir"

# My options for use with spamc and maildrop
OPTIONS="--create-prefs --max-children 5 -q -x -u vmail"

The only needed shell script for a cooperation with maildrop is as follows:

/usr/bin/clamscan.sh

#!/bin/bash
# Created by Tom Walsh, slim at ala.net
# slightly modified by Wolfgang Ziegler, nuppla at gmx.at
 
RUN=clamscan
# Enable this line, if you are using the clamav-daemon.
# RUN=clamdscan

#start
MSG=$(cat /proc/self/fd/0) # stdin -> $MSG
SCAN=$(echo "$MSG" | $RUN - --stdout --disable-summary)
EXIT="$?"
VIRUS=$(echo "$SCAN" | awk '{print $2}')
SUBJECT=$(echo "$MSG" | reformail -x Subject:)
 
if [ "$EXIT" == "1" ]; then
 SUBJECT="'''VIRUS''' [$VIRUS] $SUBJECT"
 MSG=$(echo "$MSG" | reformail -i"X-Virus-Status: INFECTED")
 MSG=$(echo "$MSG" | reformail -i"Subject: $(echo "$SUBJECT")")
else
 MSG=$(echo "$MSG" | reformail -i"X-Virus-Status: CLEAN")
fi
 
echo "$MSG"
exit 0

Using this SysCP-module users can decide, if mails will be routed through the virus-scanner or the spam-filter. Due to the law in some countries, which forbids any filtering without confirmation of the user, it is advisable to switch the filter off by default and leave it to the customer itself.

This module is used to enable any adjustment of the Spamassassin-settings directly through the SysCP Frontend. Spamassassin gets all settings from the SysCP-database. This is helpful, as you don't have to change the configfile each time you want to adjust something. Furthermore all settings are possible for each individual domains, and are not only available as a global context