How can AWS WAF be configured to rate limit requests?

AWS WAF allows you to rate limit requests using the 'Rate Limit' rule type. You can configure rules based on various criteria, such as IP address, HTTP method, URI, and query string parameters. You specify a 'Limit' (the maximum number of requests allowed within a defined 'Time Window' – typically seconds). If a request exceeds the limit, it's blocked. You can also configure 'Burst' to allow a temporary increase in requests.