Rate Limiting is an antispam solution which allows you to set a number of requests in a certain time period from an IP.
If the number of requests exceeds the threshold, the requests from that IP will be blocked for a certain amount of time.
Keep in mind that all requests to resources necessary to load a page (css, js, ajax, etc) will count towards the limit, but you can model that to your particular setup using the filters that exist in Speed.
In order to enable the SPEED Rate Limiting rule, head over to the SPEED section.
You can use the example below to create your new rule:
You can add your own IP for an extra layer of security, limiting any outside traffic, as seen in the example
After you add the rules and temper the values as needed, proceed to Add Rule & Apply Configuration.
The rule will automatically become Enabled and it will shortly take effect on your server.