<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>RegexMatchSet</a>. You then use <a>UpdateRegexMatchSet</a> to identify the part of a web request that you want AWS WAF to inspect, such as the values of the <code>User-Agent</code> header or the query string. For example, you can create a <code>RegexMatchSet</code> that contains a <code>RegexMatchTuple</code> that looks for any requests with <code>User-Agent</code> headers that match a <code>RegexPatternSet</code> with pattern <code>B[a@]dB[o0]t</code>. You can then configure AWS WAF to reject those requests.</p> <p>To create and configure a <code>RegexMatchSet</code>, perform the following steps:</p> <ol> <li> <p>Use <a>GetChangeToken</a> to get the change token that you provide in the <code>ChangeToken</code> parameter of a <code>CreateRegexMatchSet</code> request.</p> </li> <li> <p>Submit a <code>CreateRegexMatchSet</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 <code>UpdateRegexMatchSet</code> request.</p> </li> <li> <p>Submit an <a>UpdateRegexMatchSet</a> request to specify the part of the request that you want AWS WAF to inspect (for example, the header or the URI) and the value, using a <code>RegexPatternSet</code>, that you want AWS WAF to watch for.</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>