A proxy server receives from a client device a request for a network resource that is hosted at an origin server for a domain. The request is received at the proxy server 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 transmits the request to the origin server. Responsive to determining that the origin server is offline, the proxy server determines whether the requested resource is available in cache. If it is in cache, the proxy server retrieves the requested resource from the cache and transmits the requested resource to the client device.