<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>Creates a <a>RateBasedRule</a>. The <code>RateBasedRule</code> contains a <code>RateLimit</code>, which specifies the maximum number of requests that AWS WAF allows from a specified IP address in a five-minute period. The <code>RateBasedRule</code> also contains the <code>IPSet</code> objects, <code>ByteMatchSet</code> objects, and other predicates that identify the requests that you want to count or block if these requests exceed the <code>RateLimit</code>.</p> <p>If you add more than one predicate to a <code>RateBasedRule</code>, a request not only must exceed the <code>RateLimit</code>, but it also must match all the conditions to be counted or blocked. For example, suppose you add the following to a <code>RateBasedRule</code>:</p> <ul> <li> <p>An <code>IPSet</code> that matches the IP address <code>192.0.2.44/32</code> </p> </li> <li> <p>A <code>ByteMatchSet</code> that matches <code>BadBot</code> in the <code>User-Agent</code> header</p> </li> </ul> <p>Further, you specify a <code>RateLimit</code> of 1,000.</p> <p>You then add the <code>RateBasedRule</code> to a <code>WebACL</code> and specify that you want to block requests that meet the conditions in the rule. For a request to be blocked, it must come from the IP address 192.0.2.44 <i>and</i> the <code>User-Agent</code> header in the request must contain the value <code>BadBot</code>. Further, requests that match these two conditions must be received at a rate of more than 1,000 requests every five minutes. If both conditions are met and the rate is exceeded, AWS WAF blocks the requests. If the rate drops below 1,000 for a five-minute period, AWS WAF no longer blocks the requests.</p> <p>As a second example, suppose you want to limit requests to a particular page on your site. To do this, you could add the following to a <code>RateBasedRule</code>:</p> <ul> <li> <p>A <code>ByteMatchSet</code> with <code>FieldToMatch</code> of <code>URI</code> </p> </li> <li> <p>A <code>PositionalConstraint</code> of <code>STARTS_WITH</code> </p> </li> <li> <p>A <code>TargetString</code> of <code>login</code> </p> </li> </ul> <p>Further, you specify a <code>RateLimit</code> of 1,000.</p> <p>By adding this <code>RateBasedRule</code> to a <code>WebACL</code>, you could limit requests to your login page without affecting the rest of your site.</p> <p>To create and configure a <code>RateBasedRule</code>, perform the following steps:</p> <ol> <li> <p>Create and update the predicates that you want to include in the rule. For more information, see <a>CreateByteMatchSet</a>, <a>CreateIPSet</a>, and <a>CreateSqlInjectionMatchSet</a>.</p> </li> <li> <p>Use <a>GetChangeToken</a> to get the change token that you provide in the <code>ChangeToken</code> parameter of a <code>CreateRule</code> request.</p> </li> <li> <p>Submit a <code>CreateRateBasedRule</code> request.</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>UpdateRateBasedRule</code> request to specify the predicates that you want to include in the rule.</p> </li> <li> <p>Create and update a <code>WebACL</code> that contains the <code>RateBasedRule</code>. For more information, see <a>CreateWebACL</a>.</p> </li> </ol> <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>