My setup is pretty much straight forward. I have SOGo running with Apache2 and everything regarding SOGo works just fine. What I don't understand is, why my SOGo instance is reachable through all subdomains.Currently for every enabled subdomain (eg. mail.mydomain.com, www.mydomain.com, git.mydomain.com and so on) SOGo shows up whenever the suffix /SOGo follows the subdomain URL (mail.mydomain.com/SOGo, www.mydomain.com/SOGo, git.mydomain.com/SOGo and so on).What I actually want is to make SOGo reachable only through one specific subdomain, sogo.mydomain.comI thought that I would do this by simply including SOGo.conf in my configuration file for this particular subdomain, for which I want SOGo to be reachable. Every subdomain has its own VirtualHost configuration file, located in /etc/apache2/sites-available.The definition of the subdomain is    <IfModule mod_ssl.c>    <VirtualHost *:443>    # https://doc.owncloud.org/server/9.1/admin_manual/configuration_server/harden_server.html:    # While redirecting all traffic to HTTPS is good, it may not completely prevent man-in-the-middle attacks. Thus administrators are encouraged to set the HTTP Strict Transport Security header, which instructs browsers to not allow any connection to the ownCloud instance using HTTP, and it attempts to prevent site visitors from bypassing invalid certificate warnings.    # This can be achieved by setting the following settings within the Apache VirtualHost file containing the <VirtualHost *:443> entry:        <IfModule mod_headers.c>          Header always set Strict-Transport-Security max-age=15552000; includeSubDomains        </IfModule>        ServerName sogo.mydomain.com        ServerAdmin root@mydomain.com        ServerSignature Off        DocumentRoot /var/www/mydomain.com/ssl/sogo        <Directory />            Options FollowSymLinks            AllowOverride None        </Directory>        <Directory /var/www/mydomain.de/ssl/sogo/>            Options FollowSymLinks MultiViews            AllowOverride None            Require all granted        </Directory>        ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/        <Directory /usr/lib/cgi-bin>            AllowOverride None            Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch            Order allow,deny            Allow from all        </Directory>        ErrorLog ${APACHE_LOG_DIR}/hasselmann-sogo-ssl-error.log        # Possible values include: debug, info, notice, warn, error, crit,        # alert, emerg.        LogLevel warn        CustomLog ${APACHE_LOG_DIR}/ssl_access.log combined        Alias /doc/ /usr/share/doc/        <Directory /usr/share/doc/>            Options Indexes MultiViews FollowSymLinks            AllowOverride None            Order deny,allow            Deny from all            Allow from 127.0.0.0/255.0.0.0 ::1/128        </Directory>        SSLEngine on        SSLProtocol ALL -SSLv2 -SSLv3        SSLHonorCipherOrder On          SSLCipherSuite -ALL:ECDHE-RSA-AES256-SHA:DHE-RSA-CAMELLIA256-SHA:DHE-RSA-AES256-SHA        SSLVerifyDepth 10        SSLCertificateFile    /etc/letsencrypt/live/sogo.mydomain.com/fullchain.pem        SSLCertificateKeyFile /etc/letsencrypt/live/sogo.mydomain.com/privkey.pem        <FilesMatch \.(cgi|shtml|phtml|php)$>            SSLOptions +StdEnvVars        </FilesMatch>        <Directory /usr/lib/cgi-bin>            SSLOptions +StdEnvVars        </Directory>        BrowserMatch MSIE [2-6] \            nokeepalive ssl-unclean-shutdown \            downgrade-1.0 force-response-1.0        # MSIE 7 and newer should be able to use keepalive        BrowserMatch MSIE [17-9] ssl-unclean-shutdown        Include sites-available/inc/SOGo.conf    </VirtualHost>    </IfModule>inc/SOGo.conf is hardly customized:    Alias /SOGo.woa/WebServerResources/ \          /usr/lib/GNUstep/SOGo/WebServerResources/    Alias /SOGo/WebServerResources/ \          /usr/lib/GNUstep/SOGo/WebServerResources/    <Directory /usr/lib/GNUstep/SOGo/>        AllowOverride None        <IfVersion < 2.4>                  Order deny,allow            Allow from all        </IfVersion>        <IfVersion >= 2.4>            Require all granted        </IfVersion>        # Explicitly allow caching of static content to avoid browser specific behavior.        # A resource's URL MUST change in order to have the client load the new version.        <IfModule expires_module>          ExpiresActive On          ExpiresDefault access plus 1 year        </IfModule>    </Directory>    ProxyRequests Off    SetEnv proxy-nokeepalive 1    ProxyPreserveHost On    ProxyPass /SOGo http://127.0.0.1:20000/SOGo retry=0    <Proxy http://127.0.0.1:20000/SOGo>    ## adjust the following to your configuration    ## and do not forget to enable the headers module    <IfModule headers_module>      RequestHeader set x-webobjects-server-port 443      RequestHeader set x-webobjects-server-name sogo.mydomain.com      RequestHeader set x-webobjects-server-url https://sogo.mydomain.com    ## When using proxy-side autentication, you need to uncomment and    ## adjust the following line:      RequestHeader unset x-webobjects-remote-user    #  RequestHeader set x-webobjects-remote-user %{REMOTE_USER}e env=REMOTE_USER      RequestHeader set x-webobjects-server-protocol HTTP/1.0    </IfModule>      AddDefaultCharset UTF-8      Order allow,deny      Allow from all    </Proxy>    # For Apple autoconfiguration    <IfModule rewrite_module>      RewriteEngine On      RewriteRule ^/.well-known/caldav/?$ /SOGo/dav [R=301]      RewriteRule ^/.well-known/carddav/?$ /SOGo/dav [R=301]    </IfModule>Header-Module is of course loaded. I would have expected that RequestHeader set x-webobjects-server-name sogo.mydomain.com would do the trick but obviously it doesn't do so.Does anybody got a hint for me on this?
Make SOGo reachable for only one subdomain with Apache
apache httpd;apache virtualhost