       be trusted and will appear in the <strong>proxiesHeader</strong> value.
        If not specified, no proxies will be trusted.</p>
      </td></tr><tr><td><code class="attributeName">protocolHeader</code></td><td>
        <p>Name of the HTTP Header read by this valve that holds the protocol
        used by the client to connect to the proxy. If not specified, the
        default of <code>null</code> is used.</p>
      </td></tr><tr><td><code class="attributeName">portHeader</code></td><td>
        <p>