• Paket einspielen:

# apt-get install squirrelmail squirrelmail-decode ingerman wngerman

• SquirrelMail-Konfigurationsprogramm aufrufen:

# /usr/sbin/squirrelmail-configure
2 (Server Settings)
A (IMAP Settings)
8 (Server software)
dovecot
R (Return to Main Menu)
3 (Folder Defaults)
3 (Trash Folder)
Trash
4 (Sent Folder)
Sent
5 (Drafts Folder)
Drafts
R (Return to Main Menu)
10 (Languages)
1 (Default Language)
de_DE
S (Save data)
Q (Quit)

• Basis-Pfad für URL auf webmail anstatt squirrelmail festlegen:

# vi /etc/squirrelmail/apache.conf
Alias /webmail /usr/share/squirrelmail

• Zugriff von außen erlauben:

# vi /etc/squirrelmail/apache.conf
[...]
<Directory /usr/share/squirrelmail>
  Order allow,deny
  Allow from all

• Zugriff per HTTPS erzwingen:

# vi /etc/squirrelmail/apache.conf
[...]
# redirect to https when available (thanks omen@descolada.dartmouth.edu)
#
#  Note: There are multiple ways to do this, and which one is suitable for
#  your site's configuration depends. Consult the apache documentation if
#  you're unsure, as this example might not work everywhere.
#
<IfModule mod_rewrite.c>
  <IfModule mod_ssl.c>
    <Location /webmail>
      RewriteEngine on
      RewriteCond %{HTTPS} !^on$ [NC]
      RewriteRule . https://%{HTTP_HOST}%{REQUEST_URI}  [L]
    </Location>
  </IfModule>
</IfModule>

• Website konfigurieren (sicherstellen, dass SSL-Zugriff auf webmail.disorganized.de auf disorganized.de/webmail umgeleitet wird):

# vi /etc/apache2/sites-available/disorganized
<VirtualHost *:443>
[...]
    <IfModule mod_rewrite.c>
[...]
        # https://webmail.disorganized.de/... -> https://disorganized.de/webmail/...
        RewriteCond %{HTTP_HOST} ^webmail.disorganized.de$ [NC]
        RewriteRule . https://disorganized.de/webmail%{REQUEST_URI}  [R=301,L]
    </IfModule>
</VirtualHost>

<VirtualHost *:80>
    ServerName webmail.disorganized.de
    Redirect permanent / https://disorganized.de/webmail/
</VirtualHost>

• Apache-Konfigurationsschnippsel einbinden:

# ln -s /etc/squirrelmail/apache.conf /etc/apache2/conf.d/squirrelmail.conf

• Apache neu starten, SSL-Redirect testen usw.