title: Only allow IPv6 addresses in Apache
body: <p>How would I, in Apache, allow only IPv6 addresses to access my site?</p>
  
  <p>This does not work:</p>
  
  <pre><code>order deny,allow
  deny from all
  allow from ::/0
  </code></pre>
  
  <p>It says "The specified network mask is invalid."</p>
  
  <p>Reference:</p>
  
  <ul>
  <li><a href="https://www.ultratools.com/tools/ipv6CIDRToRangeResult?ipAddress=%3A%3A%2F0" rel="nofollow noreferrer">https://www.ultratools.com/tools/ipv6CIDRToRangeResult?ipAddress=%3A%3A%2F0</a></li>
  </ul>