via $_SERVER["HTTP_REFERER blocking
<p>My PHP engine keep website searched keywords and system ignores some useless keywords via:</p>

<pre><code>if (strpos($system_search, 'useless keyword') === FALSE AND 
strpos($system_search, 'waste time') === FALSE AND 
strpos($system_search, 'viagra') === FALSE AND 
net_match_ban($bad_ip, $remote_ip))
{
</code></pre>

<p>also system ignore some user agents via:</p>

<pre><code>if (!stripos($_SERVER["HTTP_USER_AGENT"], 'Baiduspider') &amp;&amp;
!stripos($_SERVER["HTTP_USER_AGENT"], 'Sogou') &amp;&amp;)
{
$db-&gt;query("INSERT IGNORE INTO sphinx (`keyword`, `ip_adress`, `time`) VALUES  ('$tmp_sphinx', '$remote_ip', '$time')");
}
</code></pre>

<p>I want block some referrers using  $_SERVER["HTTP_REFERER </p>

<p>How can i ignore referrers?</p>
