19 Install fail2ban

This is optional but recommended, because the ISPConfig monitor tries to show the fail2ban log:

apt-get install fail2ban

To make fail2ban monitor PureFTPd, SASL, and Courier, create the file /etc/fail2ban/jail.local:

vi /etc/fail2ban/jail.local

[pureftpd]

enabled  = true
port     = ftp
filter   = pureftpd
logpath  = /var/log/syslog
maxretry = 3


[sasl]

enabled  = true
port     = smtp
filter   = sasl
logpath  = /var/log/mail.log
maxretry = 5


[courierpop3]

enabled  = true
port     = pop3
filter   = courierpop3
logpath  = /var/log/mail.log
maxretry = 5


[courierpop3s]

enabled  = true
port     = pop3s
filter   = courierpop3s
logpath  = /var/log/mail.log
maxretry = 5


[courierimap]

enabled  = true
port     = imap2
filter   = courierimap
logpath  = /var/log/mail.log
maxretry = 5


[courierimaps]

enabled  = true
port     = imaps
filter   = courierimaps
logpath  = /var/log/mail.log
maxretry = 5

Then create the following five filter files:

vi /etc/fail2ban/filter.d/pureftpd.conf

[Definition]
failregex = .*pure-ftpd: \(.*@<HOST>\) \[WARNING\] Authentication failed for user.*
ignoreregex =

vi /etc/fail2ban/filter.d/courierpop3.conf

# Fail2Ban configuration file
#
# $Revision: 100 $
#

[Definition]

# Option:  failregex
# Notes.:  regex to match the password failures messages in the logfile. The
#          host must be matched by a group named "host". The tag "<HOST>" can
#          be used for standard IP/hostname matching and is only an alias for
#          (?:::f{4,6}:)?(?P<host>\S+)
# Values:  TEXT
#
failregex = pop3d: LOGIN FAILED.*ip=\[.*:<HOST>\]

# Option:  ignoreregex
# Notes.:  regex to ignore. If this regex matches, the line is ignored.
# Values:  TEXT
#
ignoreregex =

vi /etc/fail2ban/filter.d/courierpop3s.conf

# Fail2Ban configuration file
#
# $Revision: 100 $
#

[Definition]

# Option:  failregex
# Notes.:  regex to match the password failures messages in the logfile. The
#          host must be matched by a group named "host". The tag "<HOST>" can
#          be used for standard IP/hostname matching and is only an alias for
#          (?:::f{4,6}:)?(?P<host>\S+)
# Values:  TEXT
#
failregex = pop3d-ssl: LOGIN FAILED.*ip=\[.*:<HOST>\]

# Option:  ignoreregex
# Notes.:  regex to ignore. If this regex matches, the line is ignored.
# Values:  TEXT
#
ignoreregex =

vi /etc/fail2ban/filter.d/courierimap.conf

# Fail2Ban configuration file
#
# $Revision: 100 $
#

[Definition]

# Option:  failregex
# Notes.:  regex to match the password failures messages in the logfile. The
#          host must be matched by a group named "host". The tag "<HOST>" can
#          be used for standard IP/hostname matching and is only an alias for
#          (?:::f{4,6}:)?(?P<host>\S+)
# Values:  TEXT
#
failregex = imapd: LOGIN FAILED.*ip=\[.*:<HOST>\]

# Option:  ignoreregex
# Notes.:  regex to ignore. If this regex matches, the line is ignored.
# Values:  TEXT
#
ignoreregex =

vi /etc/fail2ban/filter.d/courierimaps.conf

# Fail2Ban configuration file
#
# $Revision: 100 $
#

[Definition]

# Option:  failregex
# Notes.:  regex to match the password failures messages in the logfile. The
#          host must be matched by a group named "host". The tag "<HOST>" can
#          be used for standard IP/hostname matching and is only an alias for
#          (?:::f{4,6}:)?(?P<host>\S+)
# Values:  TEXT
#
failregex = imapd-ssl: LOGIN FAILED.*ip=\[.*:<HOST>\]

# Option:  ignoreregex
# Notes.:  regex to ignore. If this regex matches, the line is ignored.
# Values:  TEXT
#
ignoreregex =

Restart fail2ban afterwards:

/etc/init.d/fail2ban restart

20 Install SquirrelMail

To install the SquirrelMail webmail client, run

apt-get install squirrelmail

Then create the following symlink...

ln -s /usr/share/squirrelmail/ /var/www/webmail

... and configure SquirrelMail:

squirrelmail-configure

We must tell SquirrelMail that we are using Courier-IMAP/-POP3:

SquirrelMail Configuration : Read: config.php (1.4.0)
---------------------------------------------------------
Main Menu --
1.  Organization Preferences
2.  Server Settings
3.  Folder Defaults
4.  General Options
5.  Themes
6.  Address Books
7.  Message of the Day (MOTD)
8.  Plugins
9.  Database
10. Languages

D.  Set pre-defined settings for specific IMAP servers

C   Turn color on
S   Save data
Q   Quit

Command >> <-- D


SquirrelMail Configuration : Read: config.php
---------------------------------------------------------
While we have been building SquirrelMail, we have discovered some
preferences that work better with some servers that don't work so
well with others.  If you select your IMAP server, this option will
set some pre-defined settings for that server.

Please note that you will still need to go through and make sure
everything is correct.  This does not change everything.  There are
only a few settings that this will change.

Please select your IMAP server:
    bincimap    = Binc IMAP server
    courier     = Courier IMAP server
    cyrus       = Cyrus IMAP server
    dovecot     = Dovecot Secure IMAP server
    exchange    = Microsoft Exchange IMAP server
    hmailserver = hMailServer
    macosx      = Mac OS X Mailserver
    mercury32   = Mercury/32
    uw          = University of Washington's IMAP server
    gmail       = IMAP access to Google mail (Gmail) accounts

    quit        = Do not change anything
Command >> <-- courier


SquirrelMail Configuration : Read: config.php
---------------------------------------------------------
While we have been building SquirrelMail, we have discovered some
preferences that work better with some servers that don't work so
well with others.  If you select your IMAP server, this option will
set some pre-defined settings for that server.

Please note that you will still need to go through and make sure
everything is correct.  This does not change everything.  There are
only a few settings that this will change.

Please select your IMAP server:
    bincimap    = Binc IMAP server
    courier     = Courier IMAP server
    cyrus       = Cyrus IMAP server
    dovecot     = Dovecot Secure IMAP server
    exchange    = Microsoft Exchange IMAP server
    hmailserver = hMailServer
    macosx      = Mac OS X Mailserver
    mercury32   = Mercury/32
    uw          = University of Washington's IMAP server

    quit        = Do not change anything
Command >> courier

              imap_server_type = courier
         default_folder_prefix = INBOX.
                  trash_folder = Trash
                   sent_folder = Sent
                  draft_folder = Drafts
            show_prefix_option = false
          default_sub_of_inbox = false
show_contain_subfolders_option = false
            optional_delimiter = .
                 delete_folder = true

Press any key to continue... <-- ENTER


SquirrelMail Configuration : Read: config.php (1.4.0)
---------------------------------------------------------
Main Menu --
1.  Organization Preferences
2.  Server Settings
3.  Folder Defaults
4.  General Options
5.  Themes
6.  Address Books
7.  Message of the Day (MOTD)
8.  Plugins
9.  Database
10. Languages

D.  Set pre-defined settings for specific IMAP servers

C   Turn color on
S   Save data
Q   Quit

Command >> <-- S


SquirrelMail Configuration : Read: config.php (1.4.0)
---------------------------------------------------------
Main Menu --
1.  Organization Preferences
2.  Server Settings
3.  Folder Defaults
4.  General Options
5.  Themes
6.  Address Books
7.  Message of the Day (MOTD)
8.  Plugins
9.  Database
10. Languages

D.  Set pre-defined settings for specific IMAP servers

C   Turn color on
S   Save data
Q   Quit

Command >> S

Data saved in config.php
Press enter to continue... <-- ENTER


SquirrelMail Configuration : Read: config.php (1.4.0)
---------------------------------------------------------
Main Menu --
1.  Organization Preferences
2.  Server Settings
3.  Folder Defaults
4.  General Options
5.  Themes
6.  Address Books
7.  Message of the Day (MOTD)
8.  Plugins
9.  Database
10. Languages

D.  Set pre-defined settings for specific IMAP servers

C   Turn color on
S   Save data
Q   Quit

Command >> <-- Q

Afterwards you can access SquirrelMail under http://server1.example.com/webmail or http://192.168.0.100/webmail: