Common subdomain for several virtual domains in Apache2

Question

I'm running a web server with Apache2 and several virtual domains. Also, there's a mail server for these domains, exposing a web interface. For each virtual domain example.com, I have the subdomain mail.example.com pointing to my webmail interface (Roundcube). It works nicely with the following configuration:

<VirtualHost *:80>
    ServerAdmin me@example.com
    ServerName mail.example.com
    ServerAlias mail.vname1.com, mail.vname2.com, mail.vname3.com, #...

    DocumentRoot /srv/www/mail/
    <Directory />
            Options FollowSymLinks
            AllowOverride None
    </Directory>
    <Directory /srv/www/mail>
            Options Indexes FollowSymLinks MultiViews
            AllowOverride None
            Order allow,deny
            allow from all
    </Directory>

    ErrorLog /var/log/apache2/mail.error.log
    LogLevel warn

    CustomLog /var/log/apache2/mail.access.log combined
</VirtualHost>

However, for each new customer, I have - among other things - to add the corresponding domain name to the list of ServerAliases.

Is there a way to automatically associate all mail.* subdomains with /srv/www/mail/?

Answer 1

The ServerAlias directive supports wildcards - you should be able to use the following to match all the 'mail' subdomains.

ServerAlias mail.*

The wildcard subdomain (i.e. *.domain.tld) is well documented, but it is hard to find any indication that the domain part can be also be a wildcard.

I have used this approach quite often for common subdomains, when I used to use Apache. The only difference being that I used a redirect to a common URL (because I wanted to use SSL, and didn't want to get a certificate for every domain). None the less, it was able to successfully capture the subdomain, so the same implementation should work in your scenario. (Of course, you still need a static ServerName directive as well).