Установка/настройка хостинг панели ISPConfig 3 на Debian

1. Install The SSH Server

If you didn't install an SSH server during the basic system installation, you can do it now:

apt-get install ssh openssh-server

From now on you can use an SSH client such as PuTTY and connect from your workstation to your Debian Squeeze server and follow the remaining steps from this tutorial

2. Install vim-nox (Optional)

I'll use vi as my text editor in this tutorial. The default vi program has some strange behaviour on Debian and Ubuntu; to fix this, we install vim-nox

apt-get install vim-nox

(You don't have to do this if you use a different text editor such as joe or nano.)

3. Configure The Network

Because the Debian Squeeze installer has configured our system to get its network settings via DHCP, we have to change that now because a server should have a static IP address. Edit /etc/network/interfaces and adjust it to your needs (in this example setup I will use the IP address 192.168.0.100) (please note that I replace allow-hotplug eth0 with auto eth0; otherwise restarting the network doesn't work, and we'd have to reboot the whole system):

vi /etc/network/interfaces

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
#allow-hotplug eth0
#iface eth0 inet dhcp
auto eth0
iface eth0 inet static
        address 192.168.0.100
        netmask 255.255.255.0
        network 192.168.0.0
        broadcast 192.168.0.255
        gateway 192.168.0.1

Then restart your network:

/etc/init.d/networking restart

Then edit /etc/hosts. Make it look like this:

vi /etc/hosts

127.0.0.1       localhost.localdomain   localhost
192.168.0.100   server1.example.com     server1

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

Now run

echo server1.example.com > /etc/hostname

/etc/init.d/hostname.sh start

Afterwards, run

hostname

hostname -f

It is important that both show server1.example.com now!

4. Update Your Debian Installation

First make sure that your /etc/apt/sources.list contains the squeeze-updates repository (this makes sure you always get the newest updates for the ClamAV virus scanner - this project publishes releases very often, and sometimes old versions stop working)

vi /etc/apt/sources.list

[...]
deb http://ftp.de.debian.org/debian/ squeeze-updates main
[...]

Run

apt-get update

to update the apt package database and

apt-get upgrade

to install the latest updates (if there are any).

5. Change The Default Shell

/bin/sh is a symlink to /bin/dash, however we need /bin/bash, not /bin/dash. Therefore we do this:

dpkg-reconfigure dash

Use dash as the default system shell (/bin/sh)? <-- No

6. Synchronize the System Clock

It is a good idea to synchronize the system clock with an NTP (network time protocol) server over the Internet. Simply run

apt-get install ntp ntpdate

and your system time will always be in sync.

7. Install Postfix, Dovecot, Saslauthd, MySQL, phpMyAdmin, rkhunter, binutils

We can install Postfix, Dovecot, Saslauthd, MySQL, phpMyAdmin, rkhunter, and binutils with a single command:

apt-get install postfix postfix-mysql postfix-doc mysql-client mysql-server 
openssl getmail4 rkhunter binutils dovecot-imapd dovecot-pop3d sudo

You will be asked the following questions:

General type of mail configuration: <-- Internet Site
System mail name: <-- server1.example.com
New password for the MySQL "root" user: <-- yourrootsqlpassword
Repeat password for the MySQL "root" user: <-- yourrootsqlpassword

Next open the TLS/SSL and submission ports in Postfix:

vi /etc/postfix/master.cf

Uncomment the submission and smtps sections (leave -o milter_macro_daemon_name=ORIGINATING as we don't need it):

[...]
submission inet n       -       -       -       -       smtpd
  -o syslog_name=postfix/submission
  -o smtpd_tls_security_level=encrypt
  -o smtpd_sasl_auth_enable=yes
  -o smtpd_client_restrictions=permit_sasl_authenticated,reject
#  -o milter_macro_daemon_name=ORIGINATING
smtps     inet  n       -       -       -       -       smtpd
  -o syslog_name=postfix/smtps
  -o smtpd_tls_wrappermode=yes
  -o smtpd_sasl_auth_enable=yes
  -o smtpd_client_restrictions=permit_sasl_authenticated,reject
#  -o milter_macro_daemon_name=ORIGINATING
[...]

Restart Postfix afterwards:

/etc/init.d/postfix restart

We want MySQL to listen on all interfaces, not just localhost, therefore we edit

/etc/mysql/my.cnf and comment out the line bind-address = 127.0.0.1:

vi /etc/mysql/my.cnf

[...]
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
#bind-address           = 127.0.0.1
[...]

Then we restart MySQL:

/etc/init.d/mysql restart

Now check that networking is enabled. Run

netstat -tap | grep mysql

The output should look like this:

root@server1:~# netstat -tap | grep mysql
tcp        0      0 *:mysql      *:*        LISTEN      10617/mysqld
root@server1:~#

8. Install Amavisd-new, SpamAssassin, And Clamav

To install amavisd-new, SpamAssassin, and ClamAV, we run

apt-get install amavisd-new spamassassin clamav clamav-daemon zoo unzip bzip2 arj 
nomarch lzop cabextract apt-listchanges libnet-ldap-perl libauthen-sasl-perl clamav-docs 
daemon libio-string-perl libio-socket-ssl-perl libnet-ident-perl zip libnet-dns-perl

The ISPConfig 3 setup uses amavisd which loads the SpamAssassin filter library internally, so we can stop SpamAssassin to free up some RAM:

/etc/init.d/spamassassin stop

update-rc.d -f spamassassin remove

9. Install Apache2, PHP5, phpMyAdmin, FCGI, suExec, Pear, And mcrypt

Apache2, PHP5, phpMyAdmin, FCGI, suExec, Pear, and mcrypt can be installed as follows:

apt-get install apache2 apache2.2-common apache2-doc apache2-mpm-prefork 
apache2-utils libexpat1 ssl-cert libapache2-mod-php5 php5 php5-common php5-gd 
php5-mysql php5-imap phpmyadmin php5-cli php5-cgi libapache2-mod-fcgid apache2-
suexec php-pear php-auth php5-curl php5-mcrypt mcrypt php5-imagick imagemagick 
libapache2-mod-suphp libruby libapache2-mod-ruby libapache2-mod-python libapache2-
mod-perl2

You will see the following questions:

Web server to reconfigure automatically: <-- apache2
Configure database for phpmyadmin with dbconfig-common? <-- No

Then run the following command to enable the Apache modules suexec, rewrite, ssl, actions, and include (plus dav, dav_fs, and auth_digest if you want to use WebDAV):

a2enmod suexec rewrite ssl actions include
a2enmod dav_fs dav auth_digest

Restart Apache afterwards:

/etc/init.d/apache2 restart

10.Install PureFTPd And Quota

PureFTPd and quota can be installed with the following command:

apt-get install pure-ftpd-common pure-ftpd-mysql quota quotatool

Edit the file /etc/default/pure-ftpd-common...

vi /etc/default/pure-ftpd-common

... and make sure the start mode is set to standalone and set VIRTUALCHROOT=true:

[...]
STANDALONE_OR_INETD=standalone
[...]
VIRTUALCHROOT=true
[...]

Edit the file /etc/inetd.conf to prevent inetd from trying to start ftp:

vi /etc/inetd.conf

If there is a line beginning withftp stream tcp, comment it out (if there's no such file, then that is fine, and you don't have to modify /etc/inetd.conf):

[...]
#:STANDARD: These are standard services.
#ftp    stream  tcp     nowait  root    /usr/sbin/tcpd /usr/sbin/pure-ftpd-wrapper
[...]

If you had to modify /etc/inetd.conf, restart inetd now:

/etc/init.d/openbsd-inetd restart

Now we configure PureFTPd to allow FTP and TLS sessions. FTP is a very insecure protocol because all passwords and all data are transferred in clear text. By using TLS, the whole communication can be encrypted, thus making FTP much more secure.

If you want to allow FTP and TLS sessions, run

echo 1 > /etc/pure-ftpd/conf/TLS

In order to use TLS, we must create an SSL certificate. I create it in /etc/ssl/private/, therefore I create that directory first:

mkdir -p /etc/ssl/private/

Afterwards, we can generate the SSL certificate as follows:

openssl req -x509 -nodes -days 7300 -newkey rsa:2048 -keyout /etc/ssl/private/
pure-ftpd.pem -out /etc/ssl/private/pure-ftpd.pem

Country Name (2 letter code) [AU]: <-- Enter your Country Name (e.g., "DE").
State or Province Name (full name) [Some-State]: <-- Enter your State or Province Name.
Locality Name (eg, city) []: <-- Enter your City. 
Organization Name (eg, company) [Internet Widgits Pty Ltd]: <-- Enter your 
Organization Name (e.g., the name of your company).
Organizational Unit Name (eg, section) []: <-- Enter your Organizational Unit Name 
(e.g. "IT Department").
Common Name (eg, YOUR name) []: <-- Enter the Fully Qualified Domain Name 
of the system (e.g. "server1.example.com").
Email Address []: <-- Enter your Email Address.

Change the permissions of the SSL certificate:

chmod 600 /etc/ssl/private/pure-ftpd.pem

Then restart PureFTPd:

/etc/init.d/pure-ftpd-mysql restart

Edit /etc/fstab. Mine looks like this (I added ,usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0 to the partition with the mount point /):

vi /etc/fstab

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    defaults        0       0
# / was on /dev/sda1 during installation
UUID=92bceda2-5ae4-4e3a-8748-b14da48fb297 /               ext3    errors=remount-
ro,usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0 0       1
# swap was on /dev/sda5 during installation
UUID=e24b3e9e-095c-4b49-af27-6363a4b7d094 none            swap    sw              0       0
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto     0       0
/dev/fd0        /media/floppy0  auto    rw,user,noauto  0       0

To enable quota, run these commands:

mount -o remount /
quotacheck -avugm
quotaon -avug

11. Install BIND DNS Server

BIND can be installed as follows:

apt-get install bind9 dnsutils

12. Install Vlogger, Webalizer, And AWstats

Vlogger, webalizer, and AWstats can be installed as follows:

apt-get install vlogger webalizer awstats geoip-database

Open /etc/cron.d/awstats afterwards...

vi /etc/cron.d/awstats

... and comment out both cron jobs in that file:

#*/10 * * * * www-data [ -x /usr/share/awstats/tools/update.sh ] && 
/usr/share/awstats/tools/update.sh
# Generate static reports:
#10 03 * * * www-data [ -x /usr/share/awstats/tools/buildstatic.sh ] && 
/usr/share/awstats/tools/buildstatic.sh

13. Install Jailkit

Jailkit is needed only if you want to chroot SSH users. It can be installed as follows (important: Jailkit must be installed before ISPConfig - it cannot be installed afterwards!):

apt-get install build-essential autoconf automake1.9 libtool flex bison debhelper

cd /tmp
wget http://olivier.sessink.nl/jailkit/jailkit-2.14.tar.gz
tar xvfz jailkit-2.14.tar.gz
cd jailkit-2.14
./debian/rules binary
cd ..
dpkg -i jailkit_2.14-1_*.deb
rm -rf jailkit-2.14*

14. Install fail2ban

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

apt-get install fail2ban

To make fail2ban monitor PureFTPd and Dovecot, 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


[dovecot-pop3imap]

enabled = true
filter = dovecot-pop3imap
action = iptables-multiport[name=dovecot-pop3imap, 
port="pop3,pop3s,imap,imaps", protocol=tcp]
logpath = /var/log/mail.log
maxretry = 5

Then create the following two 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/dovecot-pop3imap.conf

[Definition]
failregex = (?: pop3-login|imap-login): .*(?:Authentication failure|Aborted login \(auth failed|
Aborted login \(tried to use disabled|Disconnected \(auth failed|Aborted login \
(\d+ authentication attempts).*rip=(?P<host>\S*),.*
ignoreregex =

Restart fail2ban afterwards:

/etc/init.d/fail2ban restart

15. 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 Dovecot-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 >> <-- dovecot


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 >> dovecot

              imap_server_type = dovecot
         default_folder_prefix = <none>
                  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 = detect
                 delete_folder = false

Press any key to continue... <-- press a key


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 >> <-- Q

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

16. Install ISPConfig 3

To install ISPConfig 3 from the latest released version, do this:

cd /tmp
wget http://www.ispconfig.org/downloads/ISPConfig-3-stable.tar.gz
tar xfz ISPConfig-3-stable.tar.gz
cd ispconfig3_install/install/

The next step is to run

php -q install.php

This will start the ISPConfig 3 installer. The installer will configure all services like Postfix, Dovecot, etc. for you. A manual setup as required for ISPConfig 2 (perfect setup guides) is not necessary.

root@server1:/tmp/ispconfig3_install/install# php -q install.php

>> Initial configuration

Operating System: Debian 6.0 (Squeeze/Sid) or compatible

   Following will be a few questions for primary configuration so be careful.
   Default values are in [brackets] and can be accepted with <ENTER>.
   Tap in "quit" (without the quotes) to stop the installer.

Select language (en,de) [en]: <-- ENTER

Installation mode (standard,expert) [standard]: <-- ENTER

Full qualified hostname (FQDN) of the server, eg server1.domain.tld [server1.example.com]: <-- ENTER

MySQL server hostname [localhost]: <-- ENTER

MySQL root username [root]: <-- ENTER

MySQL root password []: <-- yourrootsqlpassword

MySQL database to create [dbispconfig]: <-- ENTER

MySQL charset [utf8]: <-- ENTER

Generating a 2048 bit RSA private key

....+++

............................+++

writing new private key to 'smtpd.key'

---

You are about to be asked to enter information that will be incorporated into your certificate request. What you are about to enter is what is called a Distinguished Name or a DN. There are quite a few fields but you can leave some blank For some fields there will be a default value, If you enter '.', the field will be left blank.

---

Country Name (2 letter code) [AU]: <-- ENTER

State or Province Name (full name) [Some-State]: <-- ENTER

Locality Name (eg, city) []: <-- ENTER

Organization Name (eg, company) [Internet Widgits Pty Ltd]: <-- ENTER

Organizational Unit Name (eg, section) []: <-- ENTER

Common Name (eg, YOUR name) []: <-- ENTER

Email Address []: <-- ENTER

Configuring Jailkit

Configuring Dovecot

Configuring Spamassassin

Configuring Amavisd

Configuring Getmail

Configuring Pureftpd

Configuring BIND

Configuring Apache

Configuring Vlogger

Configuring Apps vhost

Configuring Firewall

Installing ISPConfig

ISPConfig Port [8080]: <-- ENTER


Configuring DBServer

Installing ISPConfig crontab

no crontab for root

no crontab for getmail

Restarting services ...

Stopping MySQL database server: mysqld.

Starting MySQL database server: mysqld.

Checking for corrupt, not cleanly closed and upgrade needing tables..

Stopping Postfix Mail Transport Agent: postfix.

Starting Postfix Mail Transport Agent: postfix.

Stopping amavisd: amavisd-new.

Starting amavisd: amavisd-new.

Stopping ClamAV daemon: clamd.

Starting ClamAV daemon: clamd Bytecode: Security mode set to "TrustSigned".

.

If you have trouble with authentication failures,
enable auth_debug setting. See http://wiki.dovecot.org/WhyDoesItNotWork
This message goes away after the first successful login.
Restarting IMAP/POP3 mail server: dovecot.
Restarting web server: apache2 ... waiting ..
Restarting ftp server: Running: /usr/sbin/pure-ftpd-mysql-virtualchroot -l mysql:/etc/pure-ftpd/db/mysql.conf -l pam -Y 1 -8 UTF-8 -H -D -b -O clf:/var/log/pure-ftpd/transfer.log -E -u 1000 -A -B
Installation completed.
root@server1:/tmp/ispconfig3_install/install#

The installer automatically configures all underlying services, so no manual configuration is needed.

Afterwards you can access ISPConfig 3 under http://server1.example.com:8080/ or http://192.168.0.100:8080/. Log in with the username admin and the password admin (you should change the default password after your first login):

The system is now ready to be used.

16.1 ISPConfig 3 Manual

In order to learn how to use ISPConfig 3, I strongly recommend to download the ISPConfig 3 Manual.

On about 300 pages, it covers the concept behind ISPConfig (admin, resellers, clients), explains how to install and update ISPConfig 3, includes a reference for all forms and form fields in ISPConfig together with examples of valid inputs, and provides tutorials for the most common tasks in ISPConfig 3. It also lines out how to make your server more secure and comes with a troubleshooting section at the end.

16.2 ISPConfig Monitor App For Android

With the ISPConfig Monitor App, you can check your server status and find out if all services are running as expected. You can check TCP and UDP ports and ping your servers. In addition to that you can use this app to request details from servers that have ISPConfig installed (please note that the minimum installed ISPConfig 3 version with support for the ISPConfig Monitor App is 3.0.3.3!); these details include everything you know from the Monitor module in the ISPConfig Control Panel (e.g. services, mail and system logs, mail queue, CPU and memory info, disk usage, quota, OS details, RKHunter log, etc.), and of course, as ISPConfig is multiserver-capable, you can check all servers that are controlled from your ISPConfig master server.

For download and usage instructions, please visit http://www.ispconfig.org/ispconfig-3/ispconfig-monitor-app-for-android/.

17. Additional Notes

17.1 OpenVZ

If the Debian server that you've just set up in this tutorial is an OpenVZ container (virtual machine), you should do this on the host system (I'm assuming that the ID of the OpenVZ container is 101 - replace it with the correct VPSID on your system):

VPSID=101
for CAP in CHOWN DAC_READ_SEARCH SETGID SETUID NET_BIND_SERVICE NET_ADMIN SYS_CHROOT SYS_NICE CHOWN DAC_READ_SEARCH SETGID SETUID NET_BIND_SERVICE NET_ADMIN SYS_CHROOT SYS_NICE
do
  vzctl set $VPSID --capability ${CAP}:on --save
done

17.2 SquirrelMail

Lots of people have reported problems (such as getting 404 Not Found errors) using the SquirrelMail webmail package in their web sites created through ISPConfig 3. This guide explains how to configure SquirrelMail on a Debian Squeeze server so that you can use it from within your web sites (created through ISPConfig).

SquirrelMail's Apache configuration is in the file /etc/squirrelmail/apache.conf, but this file isn't loaded by Apache because it is not in the /etc/apache2/conf.d/ directory. Therefore we create a symlink called squirrelmail.conf in the /etc/apache2/conf.d/ directory that points to /etc/squirrelmail/apache.conf and reload Apache afterwards:

cd /etc/apache2/conf.d/
ln -s ../../squirrelmail/apache.conf squirrelmail.conf
/etc/init.d/apache2 reload

Now open /etc/apache2/conf.d/squirrelmail.conf...

vi /etc/apache2/conf.d/squirrelmail.conf

... and add the following lines to the <Directory /usr/share/squirrelmail></Directory> container that make sure that mod_php is used for accessing SquirrelMail, regardless of what PHP mode you select for your website in ISPConfig:

[...]
<Directory /usr/share/squirrelmail>
  Options FollowSymLinks
  <IfModule mod_php5.c>
    AddType application/x-httpd-php .php
    php_flag magic_quotes_gpc Off
    php_flag track_vars On
    php_admin_flag allow_url_fopen Off
    php_value include_path .
    php_admin_value upload_tmp_dir /var/lib/squirrelmail/tmp
    php_admin_value open_basedir /usr/share/squirrelmail:/etc/squirrelmail:/var/lib/squirrelmail:/etc/hostname:/etc/mailname:/var/spool/squirrelmail
    php_flag register_globals off
  </IfModule>
  <IfModule mod_dir.c>
    DirectoryIndex index.php
  </IfModule>
  # access to configtest is limited by default to prevent information leak
  <Files configtest.php>
    order deny,allow
    deny from all
    allow from 127.0.0.1
  </Files>
</Directory>
[...]

Create the directory /var/lib/squirrelmail/tmp...

mkdir /var/lib/squirrelmail/tmp

... and make it owned by the user www-data:

chown www-data /var/lib/squirrelmail/tmp

Reload Apache again:

/etc/init.d/apache2 reload

That's it already - /etc/apache2/conf.d/squirrelmail.conf defines an alias called /squirrelmail that points to SquirrelMail's installation directory /usr/share/squirrelmail.

You can now access SquirrelMail from your web site as follows:

http://www.example.com/squirrelmail

You can also access it from the ISPConfig control panel vhost as follows (this doesn't need any configuration in ISPConfig):

http://server1.example.com:8080/squirrelmail

If you'd like to use the alias /webmail instead of /squirrelmail, simply open /etc/apache2/conf.d/squirrelmail.conf...

vi /etc/apache2/conf.d/squirrelmail.conf

... and add the line Alias /webmail /usr/share/squirrelmail:

Alias /squirrelmail /usr/share/squirrelmail
Alias /webmail /usr/share/squirrelmail
[...]

Then reload Apache:

/etc/init.d/apache2 reload

Now you can access Squirrelmail as follows:

http://www.example.com/webmail http://server1.example.com:8080/webmail

If you'd like to define a vhost like webmail.example.com where your users can access SquirrelMail, you'd have to add the following vhost configuration to /etc/apache2/conf.d/squirrelmail.conf:

vi /etc/apache2/conf.d/squirrelmail.conf

[...]
<VirtualHost 1.2.3.4:80>
  DocumentRoot /usr/share/squirrelmail
  ServerName webmail.example.com
</VirtualHost>

Make sure you replace 1.2.3.4 with the correct IP address of your server. Of course, there must be a DNS record for webmail.example.com that points to the IP address that you use in the vhost configuration. Also make sure that the vhost webmail.example.com does not exist in ISPConfig (otherwise both vhosts will interfere with each other!).

Now reload Apache...

/etc/init.d/apache2 reload

... and you can access SquirrelMail under http://webmail.example.com!

18. Links

Debian: http://www.debian.org/ ISPConfig: http://www.ispconfig.org/