title: httpd virtualhost - redirect domains not in the list
body: <p>I'd like to do a redirect when a subdomain requested is out of scope.
  Example of my subdomains:</p>
  
  <pre><code>www.vm.com 
  client.vm.com 
  agent.vm.com 
  employee.vm.com 
  admin.vm.com
  </code></pre>
  
  <p>VirtualHost block used:</p>
  
  <pre><code>&lt;VirtualHost *:80&gt;
      DocumentRoot /home/apache/projects
      ServerName vm.com
      ServerAlias *.vm.com
  
      ErrorLog logs/vm.com-error_log
      CustomLog logs/vm.com-access_log common
  &lt;/VirtualHost&gt;
  </code></pre>
  
  <p>I can't find any negation example, only intentional redirects like this:</p>
  
  <pre><code>RewriteEngine on
  RewriteCond %{HTTP_HOST} ^sub1\.vm\.com [NC]
  RewriteRule (.*) http://www.vm.com$1 [R=301,L]
  </code></pre>
  
  <p>Is it possible to have some kind of syntax like:</p>
  
  <pre><code>!(www|client|agent|employee|admin)\.vm\.com
  </code></pre>
  
  <p>Thanks.</p>