the client <em>has to</em> present a valid Certificate</li>
<li><strong>optional_no_ca</strong>:
the client may present a valid Certificate<br />
- but it need not to be (successfully) verifiable.</li>
+ but it need not to be (successfully) verifiable. This option
+ cannot be relied upon for client authentication. </li>
</ul>
-<p>In practice only levels <strong>none</strong> and
-<strong>require</strong> are really interesting, because level
-<strong>optional</strong> doesn't work with all browsers and level
-<strong>optional_no_ca</strong> is actually against the idea of
-authentication (but can be used to establish SSL test pages, etc.)</p>
<div class="example"><h3>Example</h3><pre class="prettyprint lang-config">SSLVerifyClient require</pre>
</div>