A proxy server for limiting Internet connection speed of visitors that pose a threat. The proxy server receives from a client device a request to perform an action on an identified resource that is hosted at an origin server for a domain. The proxy server receives the request as a result of a DNS request for the domain resolving to the proxy server. The origin server is one of multiple origin servers that belong to different domains that resolve to the proxy server and are owned by different entities. The proxy server analyzes the request to determine whether a visitor belonging to the request poses a threat. If the proxy server determines that the visitor poses a threat, the proxy server reduces the speed at which the proxy server processes the request while keeping a connection to the client device open.