<note> <p>This is <b>AWS WAF Classic</b> documentation. For more information, see <a href="https://docs.aws.amazon.com/waf/latest/developerguide/classic-waf-chapter.html">AWS WAF Classic</a> in the developer guide.</p> <p> <b>For the latest version of AWS WAF</b>, use the AWS WAFV2 API and see the <a href="https://docs.aws.amazon.com/waf/latest/developerguide/waf-chapter.html">AWS WAF Developer Guide</a>. With the latest version, AWS WAF has a single set of endpoints for regional and global use. </p> </note> <p>Inserts or deletes <a>Predicate</a> objects in a <code>Rule</code>. Each <code>Predicate</code> object identifies a predicate, such as a <a>ByteMatchSet</a> or an <a>IPSet</a>, that specifies the web requests that you want to allow, block, or count. If you add more than one predicate to a <code>Rule</code>, a request must match all of the specifications to be allowed, blocked, or counted. For example, suppose that you add the following to a <code>Rule</code>: </p> <ul> <li> <p>A <code>ByteMatchSet</code> that matches the value <code>BadBot</code> in the <code>User-Agent</code> header</p> </li> <li> <p>An <code>IPSet</code> that matches the IP address <code>192.0.2.44</code> </p> </li> </ul> <p>You then add the <code>Rule</code> to a <code>WebACL</code> and specify that you want to block requests that satisfy the <code>Rule</code>. For a request to be blocked, the <code>User-Agent</code> header in the request must contain the value <code>BadBot</code> <i>and</i> the request must originate from the IP address 192.0.2.44.</p> <p>To create and configure a <code>Rule</code>, perform the following steps:</p> <ol> <li> <p>Create and update the predicates that you want to include in the <code>Rule</code>.</p> </li> <li> <p>Create the <code>Rule</code>. See <a>CreateRule</a>.</p> </li> <li> <p>Use <code>GetChangeToken</code> to get the change token that you provide in the <code>ChangeToken</code> parameter of an <a>UpdateRule</a> request.</p> </li> <li> <p>Submit an <code>UpdateRule</code> request to add predicates to the <code>Rule</code>.</p> </li> <li> <p>Create and update a <code>WebACL</code> that contains the <code>Rule</code>. See <a>CreateWebACL</a>.</p> </li> </ol> <p>If you want to replace one <code>ByteMatchSet</code> or <code>IPSet</code> with another, you delete the existing one and add the new one.</p> <p>For more information about how to use the AWS WAF API to allow or block HTTP requests, see the <a href="https://docs.aws.amazon.com/waf/latest/developerguide/">AWS WAF Developer Guide</a>.</p>